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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /mm/slub.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'mm/slub.c')
-rw-r--r--mm/slub.c6310
1 files changed, 6310 insertions, 0 deletions
diff --git a/mm/slub.c b/mm/slub.c
new file mode 100644
index 000000000..157527d71
--- /dev/null
+++ b/mm/slub.c
@@ -0,0 +1,6310 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * SLUB: A slab allocator that limits cache line use instead of queuing
+ * objects in per cpu and per node lists.
+ *
+ * The allocator synchronizes using per slab locks or atomic operations
+ * and only uses a centralized lock to manage a pool of partial slabs.
+ *
+ * (C) 2007 SGI, Christoph Lameter
+ * (C) 2011 Linux Foundation, Christoph Lameter
+ */
+
+#include <linux/mm.h>
+#include <linux/swap.h> /* struct reclaim_state */
+#include <linux/module.h>
+#include <linux/bit_spinlock.h>
+#include <linux/interrupt.h>
+#include <linux/swab.h>
+#include <linux/bitops.h>
+#include <linux/slab.h>
+#include "slab.h"
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+#include <linux/kasan.h>
+#include <linux/kmsan.h>
+#include <linux/cpu.h>
+#include <linux/cpuset.h>
+#include <linux/mempolicy.h>
+#include <linux/ctype.h>
+#include <linux/stackdepot.h>
+#include <linux/debugobjects.h>
+#include <linux/kallsyms.h>
+#include <linux/kfence.h>
+#include <linux/memory.h>
+#include <linux/math64.h>
+#include <linux/fault-inject.h>
+#include <linux/stacktrace.h>
+#include <linux/prefetch.h>
+#include <linux/memcontrol.h>
+#include <linux/random.h>
+#include <kunit/test.h>
+#include <linux/sort.h>
+
+#include <linux/debugfs.h>
+#include <trace/events/kmem.h>
+
+#include "internal.h"
+
+/*
+ * Lock order:
+ * 1. slab_mutex (Global Mutex)
+ * 2. node->list_lock (Spinlock)
+ * 3. kmem_cache->cpu_slab->lock (Local lock)
+ * 4. slab_lock(slab) (Only on some arches)
+ * 5. object_map_lock (Only for debugging)
+ *
+ * slab_mutex
+ *
+ * The role of the slab_mutex is to protect the list of all the slabs
+ * and to synchronize major metadata changes to slab cache structures.
+ * Also synchronizes memory hotplug callbacks.
+ *
+ * slab_lock
+ *
+ * The slab_lock is a wrapper around the page lock, thus it is a bit
+ * spinlock.
+ *
+ * The slab_lock is only used on arches that do not have the ability
+ * to do a cmpxchg_double. It only protects:
+ *
+ * A. slab->freelist -> List of free objects in a slab
+ * B. slab->inuse -> Number of objects in use
+ * C. slab->objects -> Number of objects in slab
+ * D. slab->frozen -> frozen state
+ *
+ * Frozen slabs
+ *
+ * If a slab is frozen then it is exempt from list management. It is not
+ * on any list except per cpu partial list. The processor that froze the
+ * slab is the one who can perform list operations on the slab. Other
+ * processors may put objects onto the freelist but the processor that
+ * froze the slab is the only one that can retrieve the objects from the
+ * slab's freelist.
+ *
+ * list_lock
+ *
+ * The list_lock protects the partial and full list on each node and
+ * the partial slab counter. If taken then no new slabs may be added or
+ * removed from the lists nor make the number of partial slabs be modified.
+ * (Note that the total number of slabs is an atomic value that may be
+ * modified without taking the list lock).
+ *
+ * The list_lock is a centralized lock and thus we avoid taking it as
+ * much as possible. As long as SLUB does not have to handle partial
+ * slabs, operations can continue without any centralized lock. F.e.
+ * allocating a long series of objects that fill up slabs does not require
+ * the list lock.
+ *
+ * For debug caches, all allocations are forced to go through a list_lock
+ * protected region to serialize against concurrent validation.
+ *
+ * cpu_slab->lock local lock
+ *
+ * This locks protect slowpath manipulation of all kmem_cache_cpu fields
+ * except the stat counters. This is a percpu structure manipulated only by
+ * the local cpu, so the lock protects against being preempted or interrupted
+ * by an irq. Fast path operations rely on lockless operations instead.
+ *
+ * On PREEMPT_RT, the local lock neither disables interrupts nor preemption
+ * which means the lockless fastpath cannot be used as it might interfere with
+ * an in-progress slow path operations. In this case the local lock is always
+ * taken but it still utilizes the freelist for the common operations.
+ *
+ * lockless fastpaths
+ *
+ * The fast path allocation (slab_alloc_node()) and freeing (do_slab_free())
+ * are fully lockless when satisfied from the percpu slab (and when
+ * cmpxchg_double is possible to use, otherwise slab_lock is taken).
+ * They also don't disable preemption or migration or irqs. They rely on
+ * the transaction id (tid) field to detect being preempted or moved to
+ * another cpu.
+ *
+ * irq, preemption, migration considerations
+ *
+ * Interrupts are disabled as part of list_lock or local_lock operations, or
+ * around the slab_lock operation, in order to make the slab allocator safe
+ * to use in the context of an irq.
+ *
+ * In addition, preemption (or migration on PREEMPT_RT) is disabled in the
+ * allocation slowpath, bulk allocation, and put_cpu_partial(), so that the
+ * local cpu doesn't change in the process and e.g. the kmem_cache_cpu pointer
+ * doesn't have to be revalidated in each section protected by the local lock.
+ *
+ * SLUB assigns one slab for allocation to each processor.
+ * Allocations only occur from these slabs called cpu slabs.
+ *
+ * Slabs with free elements are kept on a partial list and during regular
+ * operations no list for full slabs is used. If an object in a full slab is
+ * freed then the slab will show up again on the partial lists.
+ * We track full slabs for debugging purposes though because otherwise we
+ * cannot scan all objects.
+ *
+ * Slabs are freed when they become empty. Teardown and setup is
+ * minimal so we rely on the page allocators per cpu caches for
+ * fast frees and allocs.
+ *
+ * slab->frozen The slab is frozen and exempt from list processing.
+ * This means that the slab is dedicated to a purpose
+ * such as satisfying allocations for a specific
+ * processor. Objects may be freed in the slab while
+ * it is frozen but slab_free will then skip the usual
+ * list operations. It is up to the processor holding
+ * the slab to integrate the slab into the slab lists
+ * when the slab is no longer needed.
+ *
+ * One use of this flag is to mark slabs that are
+ * used for allocations. Then such a slab becomes a cpu
+ * slab. The cpu slab may be equipped with an additional
+ * freelist that allows lockless access to
+ * free objects in addition to the regular freelist
+ * that requires the slab lock.
+ *
+ * SLAB_DEBUG_FLAGS Slab requires special handling due to debug
+ * options set. This moves slab handling out of
+ * the fast path and disables lockless freelists.
+ */
+
+/*
+ * We could simply use migrate_disable()/enable() but as long as it's a
+ * function call even on !PREEMPT_RT, use inline preempt_disable() there.
+ */
+#ifndef CONFIG_PREEMPT_RT
+#define slub_get_cpu_ptr(var) get_cpu_ptr(var)
+#define slub_put_cpu_ptr(var) put_cpu_ptr(var)
+#define USE_LOCKLESS_FAST_PATH() (true)
+#else
+#define slub_get_cpu_ptr(var) \
+({ \
+ migrate_disable(); \
+ this_cpu_ptr(var); \
+})
+#define slub_put_cpu_ptr(var) \
+do { \
+ (void)(var); \
+ migrate_enable(); \
+} while (0)
+#define USE_LOCKLESS_FAST_PATH() (false)
+#endif
+
+#ifdef CONFIG_SLUB_DEBUG
+#ifdef CONFIG_SLUB_DEBUG_ON
+DEFINE_STATIC_KEY_TRUE(slub_debug_enabled);
+#else
+DEFINE_STATIC_KEY_FALSE(slub_debug_enabled);
+#endif
+#endif /* CONFIG_SLUB_DEBUG */
+
+/* Structure holding parameters for get_partial() call chain */
+struct partial_context {
+ struct slab **slab;
+ gfp_t flags;
+ unsigned int orig_size;
+};
+
+static inline bool kmem_cache_debug(struct kmem_cache *s)
+{
+ return kmem_cache_debug_flags(s, SLAB_DEBUG_FLAGS);
+}
+
+static inline bool slub_debug_orig_size(struct kmem_cache *s)
+{
+ return (kmem_cache_debug_flags(s, SLAB_STORE_USER) &&
+ (s->flags & SLAB_KMALLOC));
+}
+
+void *fixup_red_left(struct kmem_cache *s, void *p)
+{
+ if (kmem_cache_debug_flags(s, SLAB_RED_ZONE))
+ p += s->red_left_pad;
+
+ return p;
+}
+
+static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ return !kmem_cache_debug(s);
+#else
+ return false;
+#endif
+}
+
+/*
+ * Issues still to be resolved:
+ *
+ * - Support PAGE_ALLOC_DEBUG. Should be easy to do.
+ *
+ * - Variable sizing of the per node arrays
+ */
+
+/* Enable to log cmpxchg failures */
+#undef SLUB_DEBUG_CMPXCHG
+
+/*
+ * Minimum number of partial slabs. These will be left on the partial
+ * lists even if they are empty. kmem_cache_shrink may reclaim them.
+ */
+#define MIN_PARTIAL 5
+
+/*
+ * Maximum number of desirable partial slabs.
+ * The existence of more partial slabs makes kmem_cache_shrink
+ * sort the partial list by the number of objects in use.
+ */
+#define MAX_PARTIAL 10
+
+#define DEBUG_DEFAULT_FLAGS (SLAB_CONSISTENCY_CHECKS | SLAB_RED_ZONE | \
+ SLAB_POISON | SLAB_STORE_USER)
+
+/*
+ * These debug flags cannot use CMPXCHG because there might be consistency
+ * issues when checking or reading debug information
+ */
+#define SLAB_NO_CMPXCHG (SLAB_CONSISTENCY_CHECKS | SLAB_STORE_USER | \
+ SLAB_TRACE)
+
+
+/*
+ * Debugging flags that require metadata to be stored in the slab. These get
+ * disabled when slub_debug=O is used and a cache's min order increases with
+ * metadata.
+ */
+#define DEBUG_METADATA_FLAGS (SLAB_RED_ZONE | SLAB_POISON | SLAB_STORE_USER)
+
+#define OO_SHIFT 16
+#define OO_MASK ((1 << OO_SHIFT) - 1)
+#define MAX_OBJS_PER_PAGE 32767 /* since slab.objects is u15 */
+
+/* Internal SLUB flags */
+/* Poison object */
+#define __OBJECT_POISON ((slab_flags_t __force)0x80000000U)
+/* Use cmpxchg_double */
+#define __CMPXCHG_DOUBLE ((slab_flags_t __force)0x40000000U)
+
+/*
+ * Tracking user of a slab.
+ */
+#define TRACK_ADDRS_COUNT 16
+struct track {
+ unsigned long addr; /* Called from address */
+#ifdef CONFIG_STACKDEPOT
+ depot_stack_handle_t handle;
+#endif
+ int cpu; /* Was running on cpu */
+ int pid; /* Pid context */
+ unsigned long when; /* When did the operation occur */
+};
+
+enum track_item { TRACK_ALLOC, TRACK_FREE };
+
+#ifdef CONFIG_SYSFS
+static int sysfs_slab_add(struct kmem_cache *);
+static int sysfs_slab_alias(struct kmem_cache *, const char *);
+#else
+static inline int sysfs_slab_add(struct kmem_cache *s) { return 0; }
+static inline int sysfs_slab_alias(struct kmem_cache *s, const char *p)
+ { return 0; }
+#endif
+
+#if defined(CONFIG_DEBUG_FS) && defined(CONFIG_SLUB_DEBUG)
+static void debugfs_slab_add(struct kmem_cache *);
+#else
+static inline void debugfs_slab_add(struct kmem_cache *s) { }
+#endif
+
+static inline void stat(const struct kmem_cache *s, enum stat_item si)
+{
+#ifdef CONFIG_SLUB_STATS
+ /*
+ * The rmw is racy on a preemptible kernel but this is acceptable, so
+ * avoid this_cpu_add()'s irq-disable overhead.
+ */
+ raw_cpu_inc(s->cpu_slab->stat[si]);
+#endif
+}
+
+/*
+ * Tracks for which NUMA nodes we have kmem_cache_nodes allocated.
+ * Corresponds to node_state[N_NORMAL_MEMORY], but can temporarily
+ * differ during memory hotplug/hotremove operations.
+ * Protected by slab_mutex.
+ */
+static nodemask_t slab_nodes;
+
+/*
+ * Workqueue used for flush_cpu_slab().
+ */
+static struct workqueue_struct *flushwq;
+
+/********************************************************************
+ * Core slab cache functions
+ *******************************************************************/
+
+/*
+ * Returns freelist pointer (ptr). With hardening, this is obfuscated
+ * with an XOR of the address where the pointer is held and a per-cache
+ * random number.
+ */
+static inline void *freelist_ptr(const struct kmem_cache *s, void *ptr,
+ unsigned long ptr_addr)
+{
+#ifdef CONFIG_SLAB_FREELIST_HARDENED
+ /*
+ * When CONFIG_KASAN_SW/HW_TAGS is enabled, ptr_addr might be tagged.
+ * Normally, this doesn't cause any issues, as both set_freepointer()
+ * and get_freepointer() are called with a pointer with the same tag.
+ * However, there are some issues with CONFIG_SLUB_DEBUG code. For
+ * example, when __free_slub() iterates over objects in a cache, it
+ * passes untagged pointers to check_object(). check_object() in turns
+ * calls get_freepointer() with an untagged pointer, which causes the
+ * freepointer to be restored incorrectly.
+ */
+ return (void *)((unsigned long)ptr ^ s->random ^
+ swab((unsigned long)kasan_reset_tag((void *)ptr_addr)));
+#else
+ return ptr;
+#endif
+}
+
+/* Returns the freelist pointer recorded at location ptr_addr. */
+static inline void *freelist_dereference(const struct kmem_cache *s,
+ void *ptr_addr)
+{
+ return freelist_ptr(s, (void *)*(unsigned long *)(ptr_addr),
+ (unsigned long)ptr_addr);
+}
+
+static inline void *get_freepointer(struct kmem_cache *s, void *object)
+{
+ object = kasan_reset_tag(object);
+ return freelist_dereference(s, object + s->offset);
+}
+
+static void prefetch_freepointer(const struct kmem_cache *s, void *object)
+{
+ prefetchw(object + s->offset);
+}
+
+/*
+ * When running under KMSAN, get_freepointer_safe() may return an uninitialized
+ * pointer value in the case the current thread loses the race for the next
+ * memory chunk in the freelist. In that case this_cpu_cmpxchg_double() in
+ * slab_alloc_node() will fail, so the uninitialized value won't be used, but
+ * KMSAN will still check all arguments of cmpxchg because of imperfect
+ * handling of inline assembly.
+ * To work around this problem, we apply __no_kmsan_checks to ensure that
+ * get_freepointer_safe() returns initialized memory.
+ */
+__no_kmsan_checks
+static inline void *get_freepointer_safe(struct kmem_cache *s, void *object)
+{
+ unsigned long freepointer_addr;
+ void *p;
+
+ if (!debug_pagealloc_enabled_static())
+ return get_freepointer(s, object);
+
+ object = kasan_reset_tag(object);
+ freepointer_addr = (unsigned long)object + s->offset;
+ copy_from_kernel_nofault(&p, (void **)freepointer_addr, sizeof(p));
+ return freelist_ptr(s, p, freepointer_addr);
+}
+
+static inline void set_freepointer(struct kmem_cache *s, void *object, void *fp)
+{
+ unsigned long freeptr_addr = (unsigned long)object + s->offset;
+
+#ifdef CONFIG_SLAB_FREELIST_HARDENED
+ BUG_ON(object == fp); /* naive detection of double free or corruption */
+#endif
+
+ freeptr_addr = (unsigned long)kasan_reset_tag((void *)freeptr_addr);
+ *(void **)freeptr_addr = freelist_ptr(s, fp, freeptr_addr);
+}
+
+/* Loop over all objects in a slab */
+#define for_each_object(__p, __s, __addr, __objects) \
+ for (__p = fixup_red_left(__s, __addr); \
+ __p < (__addr) + (__objects) * (__s)->size; \
+ __p += (__s)->size)
+
+static inline unsigned int order_objects(unsigned int order, unsigned int size)
+{
+ return ((unsigned int)PAGE_SIZE << order) / size;
+}
+
+static inline struct kmem_cache_order_objects oo_make(unsigned int order,
+ unsigned int size)
+{
+ struct kmem_cache_order_objects x = {
+ (order << OO_SHIFT) + order_objects(order, size)
+ };
+
+ return x;
+}
+
+static inline unsigned int oo_order(struct kmem_cache_order_objects x)
+{
+ return x.x >> OO_SHIFT;
+}
+
+static inline unsigned int oo_objects(struct kmem_cache_order_objects x)
+{
+ return x.x & OO_MASK;
+}
+
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+static void slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
+{
+ unsigned int nr_slabs;
+
+ s->cpu_partial = nr_objects;
+
+ /*
+ * We take the number of objects but actually limit the number of
+ * slabs on the per cpu partial list, in order to limit excessive
+ * growth of the list. For simplicity we assume that the slabs will
+ * be half-full.
+ */
+ nr_slabs = DIV_ROUND_UP(nr_objects * 2, oo_objects(s->oo));
+ s->cpu_partial_slabs = nr_slabs;
+}
+#else
+static inline void
+slub_set_cpu_partial(struct kmem_cache *s, unsigned int nr_objects)
+{
+}
+#endif /* CONFIG_SLUB_CPU_PARTIAL */
+
+/*
+ * Per slab locking using the pagelock
+ */
+static __always_inline void slab_lock(struct slab *slab)
+{
+ struct page *page = slab_page(slab);
+
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ bit_spin_lock(PG_locked, &page->flags);
+}
+
+static __always_inline void slab_unlock(struct slab *slab)
+{
+ struct page *page = slab_page(slab);
+
+ VM_BUG_ON_PAGE(PageTail(page), page);
+ __bit_spin_unlock(PG_locked, &page->flags);
+}
+
+/*
+ * Interrupts must be disabled (for the fallback code to work right), typically
+ * by an _irqsave() lock variant. On PREEMPT_RT the preempt_disable(), which is
+ * part of bit_spin_lock(), is sufficient because the policy is not to allow any
+ * allocation/ free operation in hardirq context. Therefore nothing can
+ * interrupt the operation.
+ */
+static inline bool __cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
+ void *freelist_old, unsigned long counters_old,
+ void *freelist_new, unsigned long counters_new,
+ const char *n)
+{
+ if (USE_LOCKLESS_FAST_PATH())
+ lockdep_assert_irqs_disabled();
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+ if (s->flags & __CMPXCHG_DOUBLE) {
+ if (cmpxchg_double(&slab->freelist, &slab->counters,
+ freelist_old, counters_old,
+ freelist_new, counters_new))
+ return true;
+ } else
+#endif
+ {
+ slab_lock(slab);
+ if (slab->freelist == freelist_old &&
+ slab->counters == counters_old) {
+ slab->freelist = freelist_new;
+ slab->counters = counters_new;
+ slab_unlock(slab);
+ return true;
+ }
+ slab_unlock(slab);
+ }
+
+ cpu_relax();
+ stat(s, CMPXCHG_DOUBLE_FAIL);
+
+#ifdef SLUB_DEBUG_CMPXCHG
+ pr_info("%s %s: cmpxchg double redo ", n, s->name);
+#endif
+
+ return false;
+}
+
+static inline bool cmpxchg_double_slab(struct kmem_cache *s, struct slab *slab,
+ void *freelist_old, unsigned long counters_old,
+ void *freelist_new, unsigned long counters_new,
+ const char *n)
+{
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+ if (s->flags & __CMPXCHG_DOUBLE) {
+ if (cmpxchg_double(&slab->freelist, &slab->counters,
+ freelist_old, counters_old,
+ freelist_new, counters_new))
+ return true;
+ } else
+#endif
+ {
+ unsigned long flags;
+
+ local_irq_save(flags);
+ slab_lock(slab);
+ if (slab->freelist == freelist_old &&
+ slab->counters == counters_old) {
+ slab->freelist = freelist_new;
+ slab->counters = counters_new;
+ slab_unlock(slab);
+ local_irq_restore(flags);
+ return true;
+ }
+ slab_unlock(slab);
+ local_irq_restore(flags);
+ }
+
+ cpu_relax();
+ stat(s, CMPXCHG_DOUBLE_FAIL);
+
+#ifdef SLUB_DEBUG_CMPXCHG
+ pr_info("%s %s: cmpxchg double redo ", n, s->name);
+#endif
+
+ return false;
+}
+
+#ifdef CONFIG_SLUB_DEBUG
+static unsigned long object_map[BITS_TO_LONGS(MAX_OBJS_PER_PAGE)];
+static DEFINE_SPINLOCK(object_map_lock);
+
+static void __fill_map(unsigned long *obj_map, struct kmem_cache *s,
+ struct slab *slab)
+{
+ void *addr = slab_address(slab);
+ void *p;
+
+ bitmap_zero(obj_map, slab->objects);
+
+ for (p = slab->freelist; p; p = get_freepointer(s, p))
+ set_bit(__obj_to_index(s, addr, p), obj_map);
+}
+
+#if IS_ENABLED(CONFIG_KUNIT)
+static bool slab_add_kunit_errors(void)
+{
+ struct kunit_resource *resource;
+
+ if (likely(!current->kunit_test))
+ return false;
+
+ resource = kunit_find_named_resource(current->kunit_test, "slab_errors");
+ if (!resource)
+ return false;
+
+ (*(int *)resource->data)++;
+ kunit_put_resource(resource);
+ return true;
+}
+#else
+static inline bool slab_add_kunit_errors(void) { return false; }
+#endif
+
+static inline unsigned int size_from_object(struct kmem_cache *s)
+{
+ if (s->flags & SLAB_RED_ZONE)
+ return s->size - s->red_left_pad;
+
+ return s->size;
+}
+
+static inline void *restore_red_left(struct kmem_cache *s, void *p)
+{
+ if (s->flags & SLAB_RED_ZONE)
+ p -= s->red_left_pad;
+
+ return p;
+}
+
+/*
+ * Debug settings:
+ */
+#if defined(CONFIG_SLUB_DEBUG_ON)
+static slab_flags_t slub_debug = DEBUG_DEFAULT_FLAGS;
+#else
+static slab_flags_t slub_debug;
+#endif
+
+static char *slub_debug_string;
+static int disable_higher_order_debug;
+
+/*
+ * slub is about to manipulate internal object metadata. This memory lies
+ * outside the range of the allocated object, so accessing it would normally
+ * be reported by kasan as a bounds error. metadata_access_enable() is used
+ * to tell kasan that these accesses are OK.
+ */
+static inline void metadata_access_enable(void)
+{
+ kasan_disable_current();
+}
+
+static inline void metadata_access_disable(void)
+{
+ kasan_enable_current();
+}
+
+/*
+ * Object debugging
+ */
+
+/* Verify that a pointer has an address that is valid within a slab page */
+static inline int check_valid_pointer(struct kmem_cache *s,
+ struct slab *slab, void *object)
+{
+ void *base;
+
+ if (!object)
+ return 1;
+
+ base = slab_address(slab);
+ object = kasan_reset_tag(object);
+ object = restore_red_left(s, object);
+ if (object < base || object >= base + slab->objects * s->size ||
+ (object - base) % s->size) {
+ return 0;
+ }
+
+ return 1;
+}
+
+static void print_section(char *level, char *text, u8 *addr,
+ unsigned int length)
+{
+ metadata_access_enable();
+ print_hex_dump(level, text, DUMP_PREFIX_ADDRESS,
+ 16, 1, kasan_reset_tag((void *)addr), length, 1);
+ metadata_access_disable();
+}
+
+/*
+ * See comment in calculate_sizes().
+ */
+static inline bool freeptr_outside_object(struct kmem_cache *s)
+{
+ return s->offset >= s->inuse;
+}
+
+/*
+ * Return offset of the end of info block which is inuse + free pointer if
+ * not overlapping with object.
+ */
+static inline unsigned int get_info_end(struct kmem_cache *s)
+{
+ if (freeptr_outside_object(s))
+ return s->inuse + sizeof(void *);
+ else
+ return s->inuse;
+}
+
+static struct track *get_track(struct kmem_cache *s, void *object,
+ enum track_item alloc)
+{
+ struct track *p;
+
+ p = object + get_info_end(s);
+
+ return kasan_reset_tag(p + alloc);
+}
+
+#ifdef CONFIG_STACKDEPOT
+static noinline depot_stack_handle_t set_track_prepare(void)
+{
+ depot_stack_handle_t handle;
+ unsigned long entries[TRACK_ADDRS_COUNT];
+ unsigned int nr_entries;
+
+ nr_entries = stack_trace_save(entries, ARRAY_SIZE(entries), 3);
+ handle = stack_depot_save(entries, nr_entries, GFP_NOWAIT);
+
+ return handle;
+}
+#else
+static inline depot_stack_handle_t set_track_prepare(void)
+{
+ return 0;
+}
+#endif
+
+static void set_track_update(struct kmem_cache *s, void *object,
+ enum track_item alloc, unsigned long addr,
+ depot_stack_handle_t handle)
+{
+ struct track *p = get_track(s, object, alloc);
+
+#ifdef CONFIG_STACKDEPOT
+ p->handle = handle;
+#endif
+ p->addr = addr;
+ p->cpu = smp_processor_id();
+ p->pid = current->pid;
+ p->when = jiffies;
+}
+
+static __always_inline void set_track(struct kmem_cache *s, void *object,
+ enum track_item alloc, unsigned long addr)
+{
+ depot_stack_handle_t handle = set_track_prepare();
+
+ set_track_update(s, object, alloc, addr, handle);
+}
+
+static void init_tracking(struct kmem_cache *s, void *object)
+{
+ struct track *p;
+
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ p = get_track(s, object, TRACK_ALLOC);
+ memset(p, 0, 2*sizeof(struct track));
+}
+
+static void print_track(const char *s, struct track *t, unsigned long pr_time)
+{
+ depot_stack_handle_t handle __maybe_unused;
+
+ if (!t->addr)
+ return;
+
+ pr_err("%s in %pS age=%lu cpu=%u pid=%d\n",
+ s, (void *)t->addr, pr_time - t->when, t->cpu, t->pid);
+#ifdef CONFIG_STACKDEPOT
+ handle = READ_ONCE(t->handle);
+ if (handle)
+ stack_depot_print(handle);
+ else
+ pr_err("object allocation/free stack trace missing\n");
+#endif
+}
+
+void print_tracking(struct kmem_cache *s, void *object)
+{
+ unsigned long pr_time = jiffies;
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ print_track("Allocated", get_track(s, object, TRACK_ALLOC), pr_time);
+ print_track("Freed", get_track(s, object, TRACK_FREE), pr_time);
+}
+
+static void print_slab_info(const struct slab *slab)
+{
+ struct folio *folio = (struct folio *)slab_folio(slab);
+
+ pr_err("Slab 0x%p objects=%u used=%u fp=0x%p flags=%pGp\n",
+ slab, slab->objects, slab->inuse, slab->freelist,
+ folio_flags(folio, 0));
+}
+
+/*
+ * kmalloc caches has fixed sizes (mostly power of 2), and kmalloc() API
+ * family will round up the real request size to these fixed ones, so
+ * there could be an extra area than what is requested. Save the original
+ * request size in the meta data area, for better debug and sanity check.
+ */
+static inline void set_orig_size(struct kmem_cache *s,
+ void *object, unsigned int orig_size)
+{
+ void *p = kasan_reset_tag(object);
+
+ if (!slub_debug_orig_size(s))
+ return;
+
+ p += get_info_end(s);
+ p += sizeof(struct track) * 2;
+
+ *(unsigned int *)p = orig_size;
+}
+
+static inline unsigned int get_orig_size(struct kmem_cache *s, void *object)
+{
+ void *p = kasan_reset_tag(object);
+
+ if (!slub_debug_orig_size(s))
+ return s->object_size;
+
+ p += get_info_end(s);
+ p += sizeof(struct track) * 2;
+
+ return *(unsigned int *)p;
+}
+
+static void slab_bug(struct kmem_cache *s, char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ pr_err("=============================================================================\n");
+ pr_err("BUG %s (%s): %pV\n", s->name, print_tainted(), &vaf);
+ pr_err("-----------------------------------------------------------------------------\n\n");
+ va_end(args);
+}
+
+__printf(2, 3)
+static void slab_fix(struct kmem_cache *s, char *fmt, ...)
+{
+ struct va_format vaf;
+ va_list args;
+
+ if (slab_add_kunit_errors())
+ return;
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+ pr_err("FIX %s: %pV\n", s->name, &vaf);
+ va_end(args);
+}
+
+static void print_trailer(struct kmem_cache *s, struct slab *slab, u8 *p)
+{
+ unsigned int off; /* Offset of last byte */
+ u8 *addr = slab_address(slab);
+
+ print_tracking(s, p);
+
+ print_slab_info(slab);
+
+ pr_err("Object 0x%p @offset=%tu fp=0x%p\n\n",
+ p, p - addr, get_freepointer(s, p));
+
+ if (s->flags & SLAB_RED_ZONE)
+ print_section(KERN_ERR, "Redzone ", p - s->red_left_pad,
+ s->red_left_pad);
+ else if (p > addr + 16)
+ print_section(KERN_ERR, "Bytes b4 ", p - 16, 16);
+
+ print_section(KERN_ERR, "Object ", p,
+ min_t(unsigned int, s->object_size, PAGE_SIZE));
+ if (s->flags & SLAB_RED_ZONE)
+ print_section(KERN_ERR, "Redzone ", p + s->object_size,
+ s->inuse - s->object_size);
+
+ off = get_info_end(s);
+
+ if (s->flags & SLAB_STORE_USER)
+ off += 2 * sizeof(struct track);
+
+ if (slub_debug_orig_size(s))
+ off += sizeof(unsigned int);
+
+ off += kasan_metadata_size(s);
+
+ if (off != size_from_object(s))
+ /* Beginning of the filler is the free pointer */
+ print_section(KERN_ERR, "Padding ", p + off,
+ size_from_object(s) - off);
+
+ dump_stack();
+}
+
+static void object_err(struct kmem_cache *s, struct slab *slab,
+ u8 *object, char *reason)
+{
+ if (slab_add_kunit_errors())
+ return;
+
+ slab_bug(s, "%s", reason);
+ print_trailer(s, slab, object);
+ add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
+}
+
+static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
+ void **freelist, void *nextfree)
+{
+ if ((s->flags & SLAB_CONSISTENCY_CHECKS) &&
+ !check_valid_pointer(s, slab, nextfree) && freelist) {
+ object_err(s, slab, *freelist, "Freechain corrupt");
+ *freelist = NULL;
+ slab_fix(s, "Isolate corrupted freechain");
+ return true;
+ }
+
+ return false;
+}
+
+static __printf(3, 4) void slab_err(struct kmem_cache *s, struct slab *slab,
+ const char *fmt, ...)
+{
+ va_list args;
+ char buf[100];
+
+ if (slab_add_kunit_errors())
+ return;
+
+ va_start(args, fmt);
+ vsnprintf(buf, sizeof(buf), fmt, args);
+ va_end(args);
+ slab_bug(s, "%s", buf);
+ print_slab_info(slab);
+ dump_stack();
+ add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
+}
+
+static void init_object(struct kmem_cache *s, void *object, u8 val)
+{
+ u8 *p = kasan_reset_tag(object);
+
+ if (s->flags & SLAB_RED_ZONE)
+ memset(p - s->red_left_pad, val, s->red_left_pad);
+
+ if (s->flags & __OBJECT_POISON) {
+ memset(p, POISON_FREE, s->object_size - 1);
+ p[s->object_size - 1] = POISON_END;
+ }
+
+ if (s->flags & SLAB_RED_ZONE)
+ memset(p + s->object_size, val, s->inuse - s->object_size);
+}
+
+static void restore_bytes(struct kmem_cache *s, char *message, u8 data,
+ void *from, void *to)
+{
+ slab_fix(s, "Restoring %s 0x%p-0x%p=0x%x", message, from, to - 1, data);
+ memset(from, data, to - from);
+}
+
+static int check_bytes_and_report(struct kmem_cache *s, struct slab *slab,
+ u8 *object, char *what,
+ u8 *start, unsigned int value, unsigned int bytes)
+{
+ u8 *fault;
+ u8 *end;
+ u8 *addr = slab_address(slab);
+
+ metadata_access_enable();
+ fault = memchr_inv(kasan_reset_tag(start), value, bytes);
+ metadata_access_disable();
+ if (!fault)
+ return 1;
+
+ end = start + bytes;
+ while (end > fault && end[-1] == value)
+ end--;
+
+ if (slab_add_kunit_errors())
+ goto skip_bug_print;
+
+ slab_bug(s, "%s overwritten", what);
+ pr_err("0x%p-0x%p @offset=%tu. First byte 0x%x instead of 0x%x\n",
+ fault, end - 1, fault - addr,
+ fault[0], value);
+ print_trailer(s, slab, object);
+ add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
+
+skip_bug_print:
+ restore_bytes(s, what, value, fault, end);
+ return 0;
+}
+
+/*
+ * Object layout:
+ *
+ * object address
+ * Bytes of the object to be managed.
+ * If the freepointer may overlay the object then the free
+ * pointer is at the middle of the object.
+ *
+ * Poisoning uses 0x6b (POISON_FREE) and the last byte is
+ * 0xa5 (POISON_END)
+ *
+ * object + s->object_size
+ * Padding to reach word boundary. This is also used for Redzoning.
+ * Padding is extended by another word if Redzoning is enabled and
+ * object_size == inuse.
+ *
+ * We fill with 0xbb (RED_INACTIVE) for inactive objects and with
+ * 0xcc (RED_ACTIVE) for objects in use.
+ *
+ * object + s->inuse
+ * Meta data starts here.
+ *
+ * A. Free pointer (if we cannot overwrite object on free)
+ * B. Tracking data for SLAB_STORE_USER
+ * C. Original request size for kmalloc object (SLAB_STORE_USER enabled)
+ * D. Padding to reach required alignment boundary or at minimum
+ * one word if debugging is on to be able to detect writes
+ * before the word boundary.
+ *
+ * Padding is done using 0x5a (POISON_INUSE)
+ *
+ * object + s->size
+ * Nothing is used beyond s->size.
+ *
+ * If slabcaches are merged then the object_size and inuse boundaries are mostly
+ * ignored. And therefore no slab options that rely on these boundaries
+ * may be used with merged slabcaches.
+ */
+
+static int check_pad_bytes(struct kmem_cache *s, struct slab *slab, u8 *p)
+{
+ unsigned long off = get_info_end(s); /* The end of info */
+
+ if (s->flags & SLAB_STORE_USER) {
+ /* We also have user information there */
+ off += 2 * sizeof(struct track);
+
+ if (s->flags & SLAB_KMALLOC)
+ off += sizeof(unsigned int);
+ }
+
+ off += kasan_metadata_size(s);
+
+ if (size_from_object(s) == off)
+ return 1;
+
+ return check_bytes_and_report(s, slab, p, "Object padding",
+ p + off, POISON_INUSE, size_from_object(s) - off);
+}
+
+/* Check the pad bytes at the end of a slab page */
+static void slab_pad_check(struct kmem_cache *s, struct slab *slab)
+{
+ u8 *start;
+ u8 *fault;
+ u8 *end;
+ u8 *pad;
+ int length;
+ int remainder;
+
+ if (!(s->flags & SLAB_POISON))
+ return;
+
+ start = slab_address(slab);
+ length = slab_size(slab);
+ end = start + length;
+ remainder = length % s->size;
+ if (!remainder)
+ return;
+
+ pad = end - remainder;
+ metadata_access_enable();
+ fault = memchr_inv(kasan_reset_tag(pad), POISON_INUSE, remainder);
+ metadata_access_disable();
+ if (!fault)
+ return;
+ while (end > fault && end[-1] == POISON_INUSE)
+ end--;
+
+ slab_err(s, slab, "Padding overwritten. 0x%p-0x%p @offset=%tu",
+ fault, end - 1, fault - start);
+ print_section(KERN_ERR, "Padding ", pad, remainder);
+
+ restore_bytes(s, "slab padding", POISON_INUSE, fault, end);
+}
+
+static int check_object(struct kmem_cache *s, struct slab *slab,
+ void *object, u8 val)
+{
+ u8 *p = object;
+ u8 *endobject = object + s->object_size;
+
+ if (s->flags & SLAB_RED_ZONE) {
+ if (!check_bytes_and_report(s, slab, object, "Left Redzone",
+ object - s->red_left_pad, val, s->red_left_pad))
+ return 0;
+
+ if (!check_bytes_and_report(s, slab, object, "Right Redzone",
+ endobject, val, s->inuse - s->object_size))
+ return 0;
+ } else {
+ if ((s->flags & SLAB_POISON) && s->object_size < s->inuse) {
+ check_bytes_and_report(s, slab, p, "Alignment padding",
+ endobject, POISON_INUSE,
+ s->inuse - s->object_size);
+ }
+ }
+
+ if (s->flags & SLAB_POISON) {
+ if (val != SLUB_RED_ACTIVE && (s->flags & __OBJECT_POISON) &&
+ (!check_bytes_and_report(s, slab, p, "Poison", p,
+ POISON_FREE, s->object_size - 1) ||
+ !check_bytes_and_report(s, slab, p, "End Poison",
+ p + s->object_size - 1, POISON_END, 1)))
+ return 0;
+ /*
+ * check_pad_bytes cleans up on its own.
+ */
+ check_pad_bytes(s, slab, p);
+ }
+
+ if (!freeptr_outside_object(s) && val == SLUB_RED_ACTIVE)
+ /*
+ * Object and freepointer overlap. Cannot check
+ * freepointer while object is allocated.
+ */
+ return 1;
+
+ /* Check free pointer validity */
+ if (!check_valid_pointer(s, slab, get_freepointer(s, p))) {
+ object_err(s, slab, p, "Freepointer corrupt");
+ /*
+ * No choice but to zap it and thus lose the remainder
+ * of the free objects in this slab. May cause
+ * another error because the object count is now wrong.
+ */
+ set_freepointer(s, p, NULL);
+ return 0;
+ }
+ return 1;
+}
+
+static int check_slab(struct kmem_cache *s, struct slab *slab)
+{
+ int maxobj;
+
+ if (!folio_test_slab(slab_folio(slab))) {
+ slab_err(s, slab, "Not a valid slab page");
+ return 0;
+ }
+
+ maxobj = order_objects(slab_order(slab), s->size);
+ if (slab->objects > maxobj) {
+ slab_err(s, slab, "objects %u > max %u",
+ slab->objects, maxobj);
+ return 0;
+ }
+ if (slab->inuse > slab->objects) {
+ slab_err(s, slab, "inuse %u > max %u",
+ slab->inuse, slab->objects);
+ return 0;
+ }
+ /* Slab_pad_check fixes things up after itself */
+ slab_pad_check(s, slab);
+ return 1;
+}
+
+/*
+ * Determine if a certain object in a slab is on the freelist. Must hold the
+ * slab lock to guarantee that the chains are in a consistent state.
+ */
+static int on_freelist(struct kmem_cache *s, struct slab *slab, void *search)
+{
+ int nr = 0;
+ void *fp;
+ void *object = NULL;
+ int max_objects;
+
+ fp = slab->freelist;
+ while (fp && nr <= slab->objects) {
+ if (fp == search)
+ return 1;
+ if (!check_valid_pointer(s, slab, fp)) {
+ if (object) {
+ object_err(s, slab, object,
+ "Freechain corrupt");
+ set_freepointer(s, object, NULL);
+ } else {
+ slab_err(s, slab, "Freepointer corrupt");
+ slab->freelist = NULL;
+ slab->inuse = slab->objects;
+ slab_fix(s, "Freelist cleared");
+ return 0;
+ }
+ break;
+ }
+ object = fp;
+ fp = get_freepointer(s, object);
+ nr++;
+ }
+
+ max_objects = order_objects(slab_order(slab), s->size);
+ if (max_objects > MAX_OBJS_PER_PAGE)
+ max_objects = MAX_OBJS_PER_PAGE;
+
+ if (slab->objects != max_objects) {
+ slab_err(s, slab, "Wrong number of objects. Found %d but should be %d",
+ slab->objects, max_objects);
+ slab->objects = max_objects;
+ slab_fix(s, "Number of objects adjusted");
+ }
+ if (slab->inuse != slab->objects - nr) {
+ slab_err(s, slab, "Wrong object count. Counter is %d but counted were %d",
+ slab->inuse, slab->objects - nr);
+ slab->inuse = slab->objects - nr;
+ slab_fix(s, "Object count adjusted");
+ }
+ return search == NULL;
+}
+
+static void trace(struct kmem_cache *s, struct slab *slab, void *object,
+ int alloc)
+{
+ if (s->flags & SLAB_TRACE) {
+ pr_info("TRACE %s %s 0x%p inuse=%d fp=0x%p\n",
+ s->name,
+ alloc ? "alloc" : "free",
+ object, slab->inuse,
+ slab->freelist);
+
+ if (!alloc)
+ print_section(KERN_INFO, "Object ", (void *)object,
+ s->object_size);
+
+ dump_stack();
+ }
+}
+
+/*
+ * Tracking of fully allocated slabs for debugging purposes.
+ */
+static void add_full(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct slab *slab)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ lockdep_assert_held(&n->list_lock);
+ list_add(&slab->slab_list, &n->full);
+}
+
+static void remove_full(struct kmem_cache *s, struct kmem_cache_node *n, struct slab *slab)
+{
+ if (!(s->flags & SLAB_STORE_USER))
+ return;
+
+ lockdep_assert_held(&n->list_lock);
+ list_del(&slab->slab_list);
+}
+
+/* Tracking of the number of slabs for debugging purposes */
+static inline unsigned long slabs_node(struct kmem_cache *s, int node)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ return atomic_long_read(&n->nr_slabs);
+}
+
+static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
+{
+ return atomic_long_read(&n->nr_slabs);
+}
+
+static inline void inc_slabs_node(struct kmem_cache *s, int node, int objects)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ /*
+ * May be called early in order to allocate a slab for the
+ * kmem_cache_node structure. Solve the chicken-egg
+ * dilemma by deferring the increment of the count during
+ * bootstrap (see early_kmem_cache_node_alloc).
+ */
+ if (likely(n)) {
+ atomic_long_inc(&n->nr_slabs);
+ atomic_long_add(objects, &n->total_objects);
+ }
+}
+static inline void dec_slabs_node(struct kmem_cache *s, int node, int objects)
+{
+ struct kmem_cache_node *n = get_node(s, node);
+
+ atomic_long_dec(&n->nr_slabs);
+ atomic_long_sub(objects, &n->total_objects);
+}
+
+/* Object debug checks for alloc/free paths */
+static void setup_object_debug(struct kmem_cache *s, void *object)
+{
+ if (!kmem_cache_debug_flags(s, SLAB_STORE_USER|SLAB_RED_ZONE|__OBJECT_POISON))
+ return;
+
+ init_object(s, object, SLUB_RED_INACTIVE);
+ init_tracking(s, object);
+}
+
+static
+void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr)
+{
+ if (!kmem_cache_debug_flags(s, SLAB_POISON))
+ return;
+
+ metadata_access_enable();
+ memset(kasan_reset_tag(addr), POISON_INUSE, slab_size(slab));
+ metadata_access_disable();
+}
+
+static inline int alloc_consistency_checks(struct kmem_cache *s,
+ struct slab *slab, void *object)
+{
+ if (!check_slab(s, slab))
+ return 0;
+
+ if (!check_valid_pointer(s, slab, object)) {
+ object_err(s, slab, object, "Freelist Pointer check fails");
+ return 0;
+ }
+
+ if (!check_object(s, slab, object, SLUB_RED_INACTIVE))
+ return 0;
+
+ return 1;
+}
+
+static noinline int alloc_debug_processing(struct kmem_cache *s,
+ struct slab *slab, void *object, int orig_size)
+{
+ if (s->flags & SLAB_CONSISTENCY_CHECKS) {
+ if (!alloc_consistency_checks(s, slab, object))
+ goto bad;
+ }
+
+ /* Success. Perform special debug activities for allocs */
+ trace(s, slab, object, 1);
+ set_orig_size(s, object, orig_size);
+ init_object(s, object, SLUB_RED_ACTIVE);
+ return 1;
+
+bad:
+ if (folio_test_slab(slab_folio(slab))) {
+ /*
+ * If this is a slab page then lets do the best we can
+ * to avoid issues in the future. Marking all objects
+ * as used avoids touching the remaining objects.
+ */
+ slab_fix(s, "Marking all objects used");
+ slab->inuse = slab->objects;
+ slab->freelist = NULL;
+ }
+ return 0;
+}
+
+static inline int free_consistency_checks(struct kmem_cache *s,
+ struct slab *slab, void *object, unsigned long addr)
+{
+ if (!check_valid_pointer(s, slab, object)) {
+ slab_err(s, slab, "Invalid object pointer 0x%p", object);
+ return 0;
+ }
+
+ if (on_freelist(s, slab, object)) {
+ object_err(s, slab, object, "Object already free");
+ return 0;
+ }
+
+ if (!check_object(s, slab, object, SLUB_RED_ACTIVE))
+ return 0;
+
+ if (unlikely(s != slab->slab_cache)) {
+ if (!folio_test_slab(slab_folio(slab))) {
+ slab_err(s, slab, "Attempt to free object(0x%p) outside of slab",
+ object);
+ } else if (!slab->slab_cache) {
+ pr_err("SLUB <none>: no slab for object 0x%p.\n",
+ object);
+ dump_stack();
+ } else
+ object_err(s, slab, object,
+ "page slab pointer corrupt.");
+ return 0;
+ }
+ return 1;
+}
+
+/*
+ * Parse a block of slub_debug options. Blocks are delimited by ';'
+ *
+ * @str: start of block
+ * @flags: returns parsed flags, or DEBUG_DEFAULT_FLAGS if none specified
+ * @slabs: return start of list of slabs, or NULL when there's no list
+ * @init: assume this is initial parsing and not per-kmem-create parsing
+ *
+ * returns the start of next block if there's any, or NULL
+ */
+static char *
+parse_slub_debug_flags(char *str, slab_flags_t *flags, char **slabs, bool init)
+{
+ bool higher_order_disable = false;
+
+ /* Skip any completely empty blocks */
+ while (*str && *str == ';')
+ str++;
+
+ if (*str == ',') {
+ /*
+ * No options but restriction on slabs. This means full
+ * debugging for slabs matching a pattern.
+ */
+ *flags = DEBUG_DEFAULT_FLAGS;
+ goto check_slabs;
+ }
+ *flags = 0;
+
+ /* Determine which debug features should be switched on */
+ for (; *str && *str != ',' && *str != ';'; str++) {
+ switch (tolower(*str)) {
+ case '-':
+ *flags = 0;
+ break;
+ case 'f':
+ *flags |= SLAB_CONSISTENCY_CHECKS;
+ break;
+ case 'z':
+ *flags |= SLAB_RED_ZONE;
+ break;
+ case 'p':
+ *flags |= SLAB_POISON;
+ break;
+ case 'u':
+ *flags |= SLAB_STORE_USER;
+ break;
+ case 't':
+ *flags |= SLAB_TRACE;
+ break;
+ case 'a':
+ *flags |= SLAB_FAILSLAB;
+ break;
+ case 'o':
+ /*
+ * Avoid enabling debugging on caches if its minimum
+ * order would increase as a result.
+ */
+ higher_order_disable = true;
+ break;
+ default:
+ if (init)
+ pr_err("slub_debug option '%c' unknown. skipped\n", *str);
+ }
+ }
+check_slabs:
+ if (*str == ',')
+ *slabs = ++str;
+ else
+ *slabs = NULL;
+
+ /* Skip over the slab list */
+ while (*str && *str != ';')
+ str++;
+
+ /* Skip any completely empty blocks */
+ while (*str && *str == ';')
+ str++;
+
+ if (init && higher_order_disable)
+ disable_higher_order_debug = 1;
+
+ if (*str)
+ return str;
+ else
+ return NULL;
+}
+
+static int __init setup_slub_debug(char *str)
+{
+ slab_flags_t flags;
+ slab_flags_t global_flags;
+ char *saved_str;
+ char *slab_list;
+ bool global_slub_debug_changed = false;
+ bool slab_list_specified = false;
+
+ global_flags = DEBUG_DEFAULT_FLAGS;
+ if (*str++ != '=' || !*str)
+ /*
+ * No options specified. Switch on full debugging.
+ */
+ goto out;
+
+ saved_str = str;
+ while (str) {
+ str = parse_slub_debug_flags(str, &flags, &slab_list, true);
+
+ if (!slab_list) {
+ global_flags = flags;
+ global_slub_debug_changed = true;
+ } else {
+ slab_list_specified = true;
+ if (flags & SLAB_STORE_USER)
+ stack_depot_want_early_init();
+ }
+ }
+
+ /*
+ * For backwards compatibility, a single list of flags with list of
+ * slabs means debugging is only changed for those slabs, so the global
+ * slub_debug should be unchanged (0 or DEBUG_DEFAULT_FLAGS, depending
+ * on CONFIG_SLUB_DEBUG_ON). We can extended that to multiple lists as
+ * long as there is no option specifying flags without a slab list.
+ */
+ if (slab_list_specified) {
+ if (!global_slub_debug_changed)
+ global_flags = slub_debug;
+ slub_debug_string = saved_str;
+ }
+out:
+ slub_debug = global_flags;
+ if (slub_debug & SLAB_STORE_USER)
+ stack_depot_want_early_init();
+ if (slub_debug != 0 || slub_debug_string)
+ static_branch_enable(&slub_debug_enabled);
+ else
+ static_branch_disable(&slub_debug_enabled);
+ if ((static_branch_unlikely(&init_on_alloc) ||
+ static_branch_unlikely(&init_on_free)) &&
+ (slub_debug & SLAB_POISON))
+ pr_info("mem auto-init: SLAB_POISON will take precedence over init_on_alloc/init_on_free\n");
+ return 1;
+}
+
+__setup("slub_debug", setup_slub_debug);
+
+/*
+ * kmem_cache_flags - apply debugging options to the cache
+ * @object_size: the size of an object without meta data
+ * @flags: flags to set
+ * @name: name of the cache
+ *
+ * Debug option(s) are applied to @flags. In addition to the debug
+ * option(s), if a slab name (or multiple) is specified i.e.
+ * slub_debug=<Debug-Options>,<slab name1>,<slab name2> ...
+ * then only the select slabs will receive the debug option(s).
+ */
+slab_flags_t kmem_cache_flags(unsigned int object_size,
+ slab_flags_t flags, const char *name)
+{
+ char *iter;
+ size_t len;
+ char *next_block;
+ slab_flags_t block_flags;
+ slab_flags_t slub_debug_local = slub_debug;
+
+ if (flags & SLAB_NO_USER_FLAGS)
+ return flags;
+
+ /*
+ * If the slab cache is for debugging (e.g. kmemleak) then
+ * don't store user (stack trace) information by default,
+ * but let the user enable it via the command line below.
+ */
+ if (flags & SLAB_NOLEAKTRACE)
+ slub_debug_local &= ~SLAB_STORE_USER;
+
+ len = strlen(name);
+ next_block = slub_debug_string;
+ /* Go through all blocks of debug options, see if any matches our slab's name */
+ while (next_block) {
+ next_block = parse_slub_debug_flags(next_block, &block_flags, &iter, false);
+ if (!iter)
+ continue;
+ /* Found a block that has a slab list, search it */
+ while (*iter) {
+ char *end, *glob;
+ size_t cmplen;
+
+ end = strchrnul(iter, ',');
+ if (next_block && next_block < end)
+ end = next_block - 1;
+
+ glob = strnchr(iter, end - iter, '*');
+ if (glob)
+ cmplen = glob - iter;
+ else
+ cmplen = max_t(size_t, len, (end - iter));
+
+ if (!strncmp(name, iter, cmplen)) {
+ flags |= block_flags;
+ return flags;
+ }
+
+ if (!*end || *end == ';')
+ break;
+ iter = end + 1;
+ }
+ }
+
+ return flags | slub_debug_local;
+}
+#else /* !CONFIG_SLUB_DEBUG */
+static inline void setup_object_debug(struct kmem_cache *s, void *object) {}
+static inline
+void setup_slab_debug(struct kmem_cache *s, struct slab *slab, void *addr) {}
+
+static inline int alloc_debug_processing(struct kmem_cache *s,
+ struct slab *slab, void *object, int orig_size) { return 0; }
+
+static inline void free_debug_processing(
+ struct kmem_cache *s, struct slab *slab,
+ void *head, void *tail, int bulk_cnt,
+ unsigned long addr) {}
+
+static inline void slab_pad_check(struct kmem_cache *s, struct slab *slab) {}
+static inline int check_object(struct kmem_cache *s, struct slab *slab,
+ void *object, u8 val) { return 1; }
+static inline void set_track(struct kmem_cache *s, void *object,
+ enum track_item alloc, unsigned long addr) {}
+static inline void add_full(struct kmem_cache *s, struct kmem_cache_node *n,
+ struct slab *slab) {}
+static inline void remove_full(struct kmem_cache *s, struct kmem_cache_node *n,
+ struct slab *slab) {}
+slab_flags_t kmem_cache_flags(unsigned int object_size,
+ slab_flags_t flags, const char *name)
+{
+ return flags;
+}
+#define slub_debug 0
+
+#define disable_higher_order_debug 0
+
+static inline unsigned long slabs_node(struct kmem_cache *s, int node)
+ { return 0; }
+static inline unsigned long node_nr_slabs(struct kmem_cache_node *n)
+ { return 0; }
+static inline void inc_slabs_node(struct kmem_cache *s, int node,
+ int objects) {}
+static inline void dec_slabs_node(struct kmem_cache *s, int node,
+ int objects) {}
+
+static bool freelist_corrupted(struct kmem_cache *s, struct slab *slab,
+ void **freelist, void *nextfree)
+{
+ return false;
+}
+#endif /* CONFIG_SLUB_DEBUG */
+
+/*
+ * Hooks for other subsystems that check memory allocations. In a typical
+ * production configuration these hooks all should produce no code at all.
+ */
+static __always_inline bool slab_free_hook(struct kmem_cache *s,
+ void *x, bool init)
+{
+ kmemleak_free_recursive(x, s->flags);
+ kmsan_slab_free(s, x);
+
+ debug_check_no_locks_freed(x, s->object_size);
+
+ if (!(s->flags & SLAB_DEBUG_OBJECTS))
+ debug_check_no_obj_freed(x, s->object_size);
+
+ /* Use KCSAN to help debug racy use-after-free. */
+ if (!(s->flags & SLAB_TYPESAFE_BY_RCU))
+ __kcsan_check_access(x, s->object_size,
+ KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT);
+
+ /*
+ * As memory initialization might be integrated into KASAN,
+ * kasan_slab_free and initialization memset's must be
+ * kept together to avoid discrepancies in behavior.
+ *
+ * The initialization memset's clear the object and the metadata,
+ * but don't touch the SLAB redzone.
+ */
+ if (init) {
+ int rsize;
+
+ if (!kasan_has_integrated_init())
+ memset(kasan_reset_tag(x), 0, s->object_size);
+ rsize = (s->flags & SLAB_RED_ZONE) ? s->red_left_pad : 0;
+ memset((char *)kasan_reset_tag(x) + s->inuse, 0,
+ s->size - s->inuse - rsize);
+ }
+ /* KASAN might put x into memory quarantine, delaying its reuse. */
+ return kasan_slab_free(s, x, init);
+}
+
+static inline bool slab_free_freelist_hook(struct kmem_cache *s,
+ void **head, void **tail,
+ int *cnt)
+{
+
+ void *object;
+ void *next = *head;
+ void *old_tail = *tail ? *tail : *head;
+
+ if (is_kfence_address(next)) {
+ slab_free_hook(s, next, false);
+ return true;
+ }
+
+ /* Head and tail of the reconstructed freelist */
+ *head = NULL;
+ *tail = NULL;
+
+ do {
+ object = next;
+ next = get_freepointer(s, object);
+
+ /* If object's reuse doesn't have to be delayed */
+ if (!slab_free_hook(s, object, slab_want_init_on_free(s))) {
+ /* Move object to the new freelist */
+ set_freepointer(s, object, *head);
+ *head = object;
+ if (!*tail)
+ *tail = object;
+ } else {
+ /*
+ * Adjust the reconstructed freelist depth
+ * accordingly if object's reuse is delayed.
+ */
+ --(*cnt);
+ }
+ } while (object != old_tail);
+
+ if (*head == *tail)
+ *tail = NULL;
+
+ return *head != NULL;
+}
+
+static void *setup_object(struct kmem_cache *s, void *object)
+{
+ setup_object_debug(s, object);
+ object = kasan_init_slab_obj(s, object);
+ if (unlikely(s->ctor)) {
+ kasan_unpoison_object_data(s, object);
+ s->ctor(object);
+ kasan_poison_object_data(s, object);
+ }
+ return object;
+}
+
+/*
+ * Slab allocation and freeing
+ */
+static inline struct slab *alloc_slab_page(gfp_t flags, int node,
+ struct kmem_cache_order_objects oo)
+{
+ struct folio *folio;
+ struct slab *slab;
+ unsigned int order = oo_order(oo);
+
+ if (node == NUMA_NO_NODE)
+ folio = (struct folio *)alloc_pages(flags, order);
+ else
+ folio = (struct folio *)__alloc_pages_node(node, flags, order);
+
+ if (!folio)
+ return NULL;
+
+ slab = folio_slab(folio);
+ __folio_set_slab(folio);
+ if (page_is_pfmemalloc(folio_page(folio, 0)))
+ slab_set_pfmemalloc(slab);
+
+ return slab;
+}
+
+#ifdef CONFIG_SLAB_FREELIST_RANDOM
+/* Pre-initialize the random sequence cache */
+static int init_cache_random_seq(struct kmem_cache *s)
+{
+ unsigned int count = oo_objects(s->oo);
+ int err;
+
+ /* Bailout if already initialised */
+ if (s->random_seq)
+ return 0;
+
+ err = cache_random_seq_create(s, count, GFP_KERNEL);
+ if (err) {
+ pr_err("SLUB: Unable to initialize free list for %s\n",
+ s->name);
+ return err;
+ }
+
+ /* Transform to an offset on the set of pages */
+ if (s->random_seq) {
+ unsigned int i;
+
+ for (i = 0; i < count; i++)
+ s->random_seq[i] *= s->size;
+ }
+ return 0;
+}
+
+/* Initialize each random sequence freelist per cache */
+static void __init init_freelist_randomization(void)
+{
+ struct kmem_cache *s;
+
+ mutex_lock(&slab_mutex);
+
+ list_for_each_entry(s, &slab_caches, list)
+ init_cache_random_seq(s);
+
+ mutex_unlock(&slab_mutex);
+}
+
+/* Get the next entry on the pre-computed freelist randomized */
+static void *next_freelist_entry(struct kmem_cache *s, struct slab *slab,
+ unsigned long *pos, void *start,
+ unsigned long page_limit,
+ unsigned long freelist_count)
+{
+ unsigned int idx;
+
+ /*
+ * If the target page allocation failed, the number of objects on the
+ * page might be smaller than the usual size defined by the cache.
+ */
+ do {
+ idx = s->random_seq[*pos];
+ *pos += 1;
+ if (*pos >= freelist_count)
+ *pos = 0;
+ } while (unlikely(idx >= page_limit));
+
+ return (char *)start + idx;
+}
+
+/* Shuffle the single linked freelist based on a random pre-computed sequence */
+static bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
+{
+ void *start;
+ void *cur;
+ void *next;
+ unsigned long idx, pos, page_limit, freelist_count;
+
+ if (slab->objects < 2 || !s->random_seq)
+ return false;
+
+ freelist_count = oo_objects(s->oo);
+ pos = prandom_u32_max(freelist_count);
+
+ page_limit = slab->objects * s->size;
+ start = fixup_red_left(s, slab_address(slab));
+
+ /* First entry is used as the base of the freelist */
+ cur = next_freelist_entry(s, slab, &pos, start, page_limit,
+ freelist_count);
+ cur = setup_object(s, cur);
+ slab->freelist = cur;
+
+ for (idx = 1; idx < slab->objects; idx++) {
+ next = next_freelist_entry(s, slab, &pos, start, page_limit,
+ freelist_count);
+ next = setup_object(s, next);
+ set_freepointer(s, cur, next);
+ cur = next;
+ }
+ set_freepointer(s, cur, NULL);
+
+ return true;
+}
+#else
+static inline int init_cache_random_seq(struct kmem_cache *s)
+{
+ return 0;
+}
+static inline void init_freelist_randomization(void) { }
+static inline bool shuffle_freelist(struct kmem_cache *s, struct slab *slab)
+{
+ return false;
+}
+#endif /* CONFIG_SLAB_FREELIST_RANDOM */
+
+static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, int node)
+{
+ struct slab *slab;
+ struct kmem_cache_order_objects oo = s->oo;
+ gfp_t alloc_gfp;
+ void *start, *p, *next;
+ int idx;
+ bool shuffle;
+
+ flags &= gfp_allowed_mask;
+
+ flags |= s->allocflags;
+
+ /*
+ * Let the initial higher-order allocation fail under memory pressure
+ * so we fall-back to the minimum order allocation.
+ */
+ alloc_gfp = (flags | __GFP_NOWARN | __GFP_NORETRY) & ~__GFP_NOFAIL;
+ if ((alloc_gfp & __GFP_DIRECT_RECLAIM) && oo_order(oo) > oo_order(s->min))
+ alloc_gfp = (alloc_gfp | __GFP_NOMEMALLOC) & ~__GFP_RECLAIM;
+
+ slab = alloc_slab_page(alloc_gfp, node, oo);
+ if (unlikely(!slab)) {
+ oo = s->min;
+ alloc_gfp = flags;
+ /*
+ * Allocation may have failed due to fragmentation.
+ * Try a lower order alloc if possible
+ */
+ slab = alloc_slab_page(alloc_gfp, node, oo);
+ if (unlikely(!slab))
+ return NULL;
+ stat(s, ORDER_FALLBACK);
+ }
+
+ slab->objects = oo_objects(oo);
+ slab->inuse = 0;
+ slab->frozen = 0;
+
+ account_slab(slab, oo_order(oo), s, flags);
+
+ slab->slab_cache = s;
+
+ kasan_poison_slab(slab);
+
+ start = slab_address(slab);
+
+ setup_slab_debug(s, slab, start);
+
+ shuffle = shuffle_freelist(s, slab);
+
+ if (!shuffle) {
+ start = fixup_red_left(s, start);
+ start = setup_object(s, start);
+ slab->freelist = start;
+ for (idx = 0, p = start; idx < slab->objects - 1; idx++) {
+ next = p + s->size;
+ next = setup_object(s, next);
+ set_freepointer(s, p, next);
+ p = next;
+ }
+ set_freepointer(s, p, NULL);
+ }
+
+ return slab;
+}
+
+static struct slab *new_slab(struct kmem_cache *s, gfp_t flags, int node)
+{
+ if (unlikely(flags & GFP_SLAB_BUG_MASK))
+ flags = kmalloc_fix_flags(flags);
+
+ WARN_ON_ONCE(s->ctor && (flags & __GFP_ZERO));
+
+ return allocate_slab(s,
+ flags & (GFP_RECLAIM_MASK | GFP_CONSTRAINT_MASK), node);
+}
+
+static void __free_slab(struct kmem_cache *s, struct slab *slab)
+{
+ struct folio *folio = slab_folio(slab);
+ int order = folio_order(folio);
+ int pages = 1 << order;
+
+ if (kmem_cache_debug_flags(s, SLAB_CONSISTENCY_CHECKS)) {
+ void *p;
+
+ slab_pad_check(s, slab);
+ for_each_object(p, s, slab_address(slab), slab->objects)
+ check_object(s, slab, p, SLUB_RED_INACTIVE);
+ }
+
+ __slab_clear_pfmemalloc(slab);
+ __folio_clear_slab(folio);
+ folio->mapping = NULL;
+ if (current->reclaim_state)
+ current->reclaim_state->reclaimed_slab += pages;
+ unaccount_slab(slab, order, s);
+ __free_pages(folio_page(folio, 0), order);
+}
+
+static void rcu_free_slab(struct rcu_head *h)
+{
+ struct slab *slab = container_of(h, struct slab, rcu_head);
+
+ __free_slab(slab->slab_cache, slab);
+}
+
+static void free_slab(struct kmem_cache *s, struct slab *slab)
+{
+ if (unlikely(s->flags & SLAB_TYPESAFE_BY_RCU)) {
+ call_rcu(&slab->rcu_head, rcu_free_slab);
+ } else
+ __free_slab(s, slab);
+}
+
+static void discard_slab(struct kmem_cache *s, struct slab *slab)
+{
+ dec_slabs_node(s, slab_nid(slab), slab->objects);
+ free_slab(s, slab);
+}
+
+/*
+ * Management of partially allocated slabs.
+ */
+static inline void
+__add_partial(struct kmem_cache_node *n, struct slab *slab, int tail)
+{
+ n->nr_partial++;
+ if (tail == DEACTIVATE_TO_TAIL)
+ list_add_tail(&slab->slab_list, &n->partial);
+ else
+ list_add(&slab->slab_list, &n->partial);
+}
+
+static inline void add_partial(struct kmem_cache_node *n,
+ struct slab *slab, int tail)
+{
+ lockdep_assert_held(&n->list_lock);
+ __add_partial(n, slab, tail);
+}
+
+static inline void remove_partial(struct kmem_cache_node *n,
+ struct slab *slab)
+{
+ lockdep_assert_held(&n->list_lock);
+ list_del(&slab->slab_list);
+ n->nr_partial--;
+}
+
+/*
+ * Called only for kmem_cache_debug() caches instead of acquire_slab(), with a
+ * slab from the n->partial list. Remove only a single object from the slab, do
+ * the alloc_debug_processing() checks and leave the slab on the list, or move
+ * it to full list if it was the last free object.
+ */
+static void *alloc_single_from_partial(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct slab *slab, int orig_size)
+{
+ void *object;
+
+ lockdep_assert_held(&n->list_lock);
+
+ object = slab->freelist;
+ slab->freelist = get_freepointer(s, object);
+ slab->inuse++;
+
+ if (!alloc_debug_processing(s, slab, object, orig_size)) {
+ remove_partial(n, slab);
+ return NULL;
+ }
+
+ if (slab->inuse == slab->objects) {
+ remove_partial(n, slab);
+ add_full(s, n, slab);
+ }
+
+ return object;
+}
+
+/*
+ * Called only for kmem_cache_debug() caches to allocate from a freshly
+ * allocated slab. Allocate a single object instead of whole freelist
+ * and put the slab to the partial (or full) list.
+ */
+static void *alloc_single_from_new_slab(struct kmem_cache *s,
+ struct slab *slab, int orig_size)
+{
+ int nid = slab_nid(slab);
+ struct kmem_cache_node *n = get_node(s, nid);
+ unsigned long flags;
+ void *object;
+
+
+ object = slab->freelist;
+ slab->freelist = get_freepointer(s, object);
+ slab->inuse = 1;
+
+ if (!alloc_debug_processing(s, slab, object, orig_size))
+ /*
+ * It's not really expected that this would fail on a
+ * freshly allocated slab, but a concurrent memory
+ * corruption in theory could cause that.
+ */
+ return NULL;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+
+ if (slab->inuse == slab->objects)
+ add_full(s, n, slab);
+ else
+ add_partial(n, slab, DEACTIVATE_TO_HEAD);
+
+ inc_slabs_node(s, nid, slab->objects);
+ spin_unlock_irqrestore(&n->list_lock, flags);
+
+ return object;
+}
+
+/*
+ * Remove slab from the partial list, freeze it and
+ * return the pointer to the freelist.
+ *
+ * Returns a list of objects or NULL if it fails.
+ */
+static inline void *acquire_slab(struct kmem_cache *s,
+ struct kmem_cache_node *n, struct slab *slab,
+ int mode)
+{
+ void *freelist;
+ unsigned long counters;
+ struct slab new;
+
+ lockdep_assert_held(&n->list_lock);
+
+ /*
+ * Zap the freelist and set the frozen bit.
+ * The old freelist is the list of objects for the
+ * per cpu allocation list.
+ */
+ freelist = slab->freelist;
+ counters = slab->counters;
+ new.counters = counters;
+ if (mode) {
+ new.inuse = slab->objects;
+ new.freelist = NULL;
+ } else {
+ new.freelist = freelist;
+ }
+
+ VM_BUG_ON(new.frozen);
+ new.frozen = 1;
+
+ if (!__cmpxchg_double_slab(s, slab,
+ freelist, counters,
+ new.freelist, new.counters,
+ "acquire_slab"))
+ return NULL;
+
+ remove_partial(n, slab);
+ WARN_ON(!freelist);
+ return freelist;
+}
+
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain);
+#else
+static inline void put_cpu_partial(struct kmem_cache *s, struct slab *slab,
+ int drain) { }
+#endif
+static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags);
+
+/*
+ * Try to allocate a partial slab from a specific node.
+ */
+static void *get_partial_node(struct kmem_cache *s, struct kmem_cache_node *n,
+ struct partial_context *pc)
+{
+ struct slab *slab, *slab2;
+ void *object = NULL;
+ unsigned long flags;
+ unsigned int partial_slabs = 0;
+
+ /*
+ * Racy check. If we mistakenly see no partial slabs then we
+ * just allocate an empty slab. If we mistakenly try to get a
+ * partial slab and there is none available then get_partial()
+ * will return NULL.
+ */
+ if (!n || !n->nr_partial)
+ return NULL;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry_safe(slab, slab2, &n->partial, slab_list) {
+ void *t;
+
+ if (!pfmemalloc_match(slab, pc->flags))
+ continue;
+
+ if (kmem_cache_debug(s)) {
+ object = alloc_single_from_partial(s, n, slab,
+ pc->orig_size);
+ if (object)
+ break;
+ continue;
+ }
+
+ t = acquire_slab(s, n, slab, object == NULL);
+ if (!t)
+ break;
+
+ if (!object) {
+ *pc->slab = slab;
+ stat(s, ALLOC_FROM_PARTIAL);
+ object = t;
+ } else {
+ put_cpu_partial(s, slab, 0);
+ stat(s, CPU_PARTIAL_NODE);
+ partial_slabs++;
+ }
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ if (!kmem_cache_has_cpu_partial(s)
+ || partial_slabs > s->cpu_partial_slabs / 2)
+ break;
+#else
+ break;
+#endif
+
+ }
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ return object;
+}
+
+/*
+ * Get a slab from somewhere. Search in increasing NUMA distances.
+ */
+static void *get_any_partial(struct kmem_cache *s, struct partial_context *pc)
+{
+#ifdef CONFIG_NUMA
+ struct zonelist *zonelist;
+ struct zoneref *z;
+ struct zone *zone;
+ enum zone_type highest_zoneidx = gfp_zone(pc->flags);
+ void *object;
+ unsigned int cpuset_mems_cookie;
+
+ /*
+ * The defrag ratio allows a configuration of the tradeoffs between
+ * inter node defragmentation and node local allocations. A lower
+ * defrag_ratio increases the tendency to do local allocations
+ * instead of attempting to obtain partial slabs from other nodes.
+ *
+ * If the defrag_ratio is set to 0 then kmalloc() always
+ * returns node local objects. If the ratio is higher then kmalloc()
+ * may return off node objects because partial slabs are obtained
+ * from other nodes and filled up.
+ *
+ * If /sys/kernel/slab/xx/remote_node_defrag_ratio is set to 100
+ * (which makes defrag_ratio = 1000) then every (well almost)
+ * allocation will first attempt to defrag slab caches on other nodes.
+ * This means scanning over all nodes to look for partial slabs which
+ * may be expensive if we do it every time we are trying to find a slab
+ * with available objects.
+ */
+ if (!s->remote_node_defrag_ratio ||
+ get_cycles() % 1024 > s->remote_node_defrag_ratio)
+ return NULL;
+
+ do {
+ cpuset_mems_cookie = read_mems_allowed_begin();
+ zonelist = node_zonelist(mempolicy_slab_node(), pc->flags);
+ for_each_zone_zonelist(zone, z, zonelist, highest_zoneidx) {
+ struct kmem_cache_node *n;
+
+ n = get_node(s, zone_to_nid(zone));
+
+ if (n && cpuset_zone_allowed(zone, pc->flags) &&
+ n->nr_partial > s->min_partial) {
+ object = get_partial_node(s, n, pc);
+ if (object) {
+ /*
+ * Don't check read_mems_allowed_retry()
+ * here - if mems_allowed was updated in
+ * parallel, that was a harmless race
+ * between allocation and the cpuset
+ * update
+ */
+ return object;
+ }
+ }
+ }
+ } while (read_mems_allowed_retry(cpuset_mems_cookie));
+#endif /* CONFIG_NUMA */
+ return NULL;
+}
+
+/*
+ * Get a partial slab, lock it and return it.
+ */
+static void *get_partial(struct kmem_cache *s, int node, struct partial_context *pc)
+{
+ void *object;
+ int searchnode = node;
+
+ if (node == NUMA_NO_NODE)
+ searchnode = numa_mem_id();
+
+ object = get_partial_node(s, get_node(s, searchnode), pc);
+ if (object || node != NUMA_NO_NODE)
+ return object;
+
+ return get_any_partial(s, pc);
+}
+
+#ifdef CONFIG_PREEMPTION
+/*
+ * Calculate the next globally unique transaction for disambiguation
+ * during cmpxchg. The transactions start with the cpu number and are then
+ * incremented by CONFIG_NR_CPUS.
+ */
+#define TID_STEP roundup_pow_of_two(CONFIG_NR_CPUS)
+#else
+/*
+ * No preemption supported therefore also no need to check for
+ * different cpus.
+ */
+#define TID_STEP 1
+#endif
+
+static inline unsigned long next_tid(unsigned long tid)
+{
+ return tid + TID_STEP;
+}
+
+#ifdef SLUB_DEBUG_CMPXCHG
+static inline unsigned int tid_to_cpu(unsigned long tid)
+{
+ return tid % TID_STEP;
+}
+
+static inline unsigned long tid_to_event(unsigned long tid)
+{
+ return tid / TID_STEP;
+}
+#endif
+
+static inline unsigned int init_tid(int cpu)
+{
+ return cpu;
+}
+
+static inline void note_cmpxchg_failure(const char *n,
+ const struct kmem_cache *s, unsigned long tid)
+{
+#ifdef SLUB_DEBUG_CMPXCHG
+ unsigned long actual_tid = __this_cpu_read(s->cpu_slab->tid);
+
+ pr_info("%s %s: cmpxchg redo ", n, s->name);
+
+#ifdef CONFIG_PREEMPTION
+ if (tid_to_cpu(tid) != tid_to_cpu(actual_tid))
+ pr_warn("due to cpu change %d -> %d\n",
+ tid_to_cpu(tid), tid_to_cpu(actual_tid));
+ else
+#endif
+ if (tid_to_event(tid) != tid_to_event(actual_tid))
+ pr_warn("due to cpu running other code. Event %ld->%ld\n",
+ tid_to_event(tid), tid_to_event(actual_tid));
+ else
+ pr_warn("for unknown reason: actual=%lx was=%lx target=%lx\n",
+ actual_tid, tid, next_tid(tid));
+#endif
+ stat(s, CMPXCHG_DOUBLE_CPU_FAIL);
+}
+
+static void init_kmem_cache_cpus(struct kmem_cache *s)
+{
+ int cpu;
+ struct kmem_cache_cpu *c;
+
+ for_each_possible_cpu(cpu) {
+ c = per_cpu_ptr(s->cpu_slab, cpu);
+ local_lock_init(&c->lock);
+ c->tid = init_tid(cpu);
+ }
+}
+
+/*
+ * Finishes removing the cpu slab. Merges cpu's freelist with slab's freelist,
+ * unfreezes the slabs and puts it on the proper list.
+ * Assumes the slab has been already safely taken away from kmem_cache_cpu
+ * by the caller.
+ */
+static void deactivate_slab(struct kmem_cache *s, struct slab *slab,
+ void *freelist)
+{
+ enum slab_modes { M_NONE, M_PARTIAL, M_FULL, M_FREE, M_FULL_NOLIST };
+ struct kmem_cache_node *n = get_node(s, slab_nid(slab));
+ int free_delta = 0;
+ enum slab_modes mode = M_NONE;
+ void *nextfree, *freelist_iter, *freelist_tail;
+ int tail = DEACTIVATE_TO_HEAD;
+ unsigned long flags = 0;
+ struct slab new;
+ struct slab old;
+
+ if (slab->freelist) {
+ stat(s, DEACTIVATE_REMOTE_FREES);
+ tail = DEACTIVATE_TO_TAIL;
+ }
+
+ /*
+ * Stage one: Count the objects on cpu's freelist as free_delta and
+ * remember the last object in freelist_tail for later splicing.
+ */
+ freelist_tail = NULL;
+ freelist_iter = freelist;
+ while (freelist_iter) {
+ nextfree = get_freepointer(s, freelist_iter);
+
+ /*
+ * If 'nextfree' is invalid, it is possible that the object at
+ * 'freelist_iter' is already corrupted. So isolate all objects
+ * starting at 'freelist_iter' by skipping them.
+ */
+ if (freelist_corrupted(s, slab, &freelist_iter, nextfree))
+ break;
+
+ freelist_tail = freelist_iter;
+ free_delta++;
+
+ freelist_iter = nextfree;
+ }
+
+ /*
+ * Stage two: Unfreeze the slab while splicing the per-cpu
+ * freelist to the head of slab's freelist.
+ *
+ * Ensure that the slab is unfrozen while the list presence
+ * reflects the actual number of objects during unfreeze.
+ *
+ * We first perform cmpxchg holding lock and insert to list
+ * when it succeed. If there is mismatch then the slab is not
+ * unfrozen and number of objects in the slab may have changed.
+ * Then release lock and retry cmpxchg again.
+ */
+redo:
+
+ old.freelist = READ_ONCE(slab->freelist);
+ old.counters = READ_ONCE(slab->counters);
+ VM_BUG_ON(!old.frozen);
+
+ /* Determine target state of the slab */
+ new.counters = old.counters;
+ if (freelist_tail) {
+ new.inuse -= free_delta;
+ set_freepointer(s, freelist_tail, old.freelist);
+ new.freelist = freelist;
+ } else
+ new.freelist = old.freelist;
+
+ new.frozen = 0;
+
+ if (!new.inuse && n->nr_partial >= s->min_partial) {
+ mode = M_FREE;
+ } else if (new.freelist) {
+ mode = M_PARTIAL;
+ /*
+ * Taking the spinlock removes the possibility that
+ * acquire_slab() will see a slab that is frozen
+ */
+ spin_lock_irqsave(&n->list_lock, flags);
+ } else if (kmem_cache_debug_flags(s, SLAB_STORE_USER)) {
+ mode = M_FULL;
+ /*
+ * This also ensures that the scanning of full
+ * slabs from diagnostic functions will not see
+ * any frozen slabs.
+ */
+ spin_lock_irqsave(&n->list_lock, flags);
+ } else {
+ mode = M_FULL_NOLIST;
+ }
+
+
+ if (!cmpxchg_double_slab(s, slab,
+ old.freelist, old.counters,
+ new.freelist, new.counters,
+ "unfreezing slab")) {
+ if (mode == M_PARTIAL || mode == M_FULL)
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ goto redo;
+ }
+
+
+ if (mode == M_PARTIAL) {
+ add_partial(n, slab, tail);
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ stat(s, tail);
+ } else if (mode == M_FREE) {
+ stat(s, DEACTIVATE_EMPTY);
+ discard_slab(s, slab);
+ stat(s, FREE_SLAB);
+ } else if (mode == M_FULL) {
+ add_full(s, n, slab);
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ stat(s, DEACTIVATE_FULL);
+ } else if (mode == M_FULL_NOLIST) {
+ stat(s, DEACTIVATE_FULL);
+ }
+}
+
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+static void __unfreeze_partials(struct kmem_cache *s, struct slab *partial_slab)
+{
+ struct kmem_cache_node *n = NULL, *n2 = NULL;
+ struct slab *slab, *slab_to_discard = NULL;
+ unsigned long flags = 0;
+
+ while (partial_slab) {
+ struct slab new;
+ struct slab old;
+
+ slab = partial_slab;
+ partial_slab = slab->next;
+
+ n2 = get_node(s, slab_nid(slab));
+ if (n != n2) {
+ if (n)
+ spin_unlock_irqrestore(&n->list_lock, flags);
+
+ n = n2;
+ spin_lock_irqsave(&n->list_lock, flags);
+ }
+
+ do {
+
+ old.freelist = slab->freelist;
+ old.counters = slab->counters;
+ VM_BUG_ON(!old.frozen);
+
+ new.counters = old.counters;
+ new.freelist = old.freelist;
+
+ new.frozen = 0;
+
+ } while (!__cmpxchg_double_slab(s, slab,
+ old.freelist, old.counters,
+ new.freelist, new.counters,
+ "unfreezing slab"));
+
+ if (unlikely(!new.inuse && n->nr_partial >= s->min_partial)) {
+ slab->next = slab_to_discard;
+ slab_to_discard = slab;
+ } else {
+ add_partial(n, slab, DEACTIVATE_TO_TAIL);
+ stat(s, FREE_ADD_PARTIAL);
+ }
+ }
+
+ if (n)
+ spin_unlock_irqrestore(&n->list_lock, flags);
+
+ while (slab_to_discard) {
+ slab = slab_to_discard;
+ slab_to_discard = slab_to_discard->next;
+
+ stat(s, DEACTIVATE_EMPTY);
+ discard_slab(s, slab);
+ stat(s, FREE_SLAB);
+ }
+}
+
+/*
+ * Unfreeze all the cpu partial slabs.
+ */
+static void unfreeze_partials(struct kmem_cache *s)
+{
+ struct slab *partial_slab;
+ unsigned long flags;
+
+ local_lock_irqsave(&s->cpu_slab->lock, flags);
+ partial_slab = this_cpu_read(s->cpu_slab->partial);
+ this_cpu_write(s->cpu_slab->partial, NULL);
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+
+ if (partial_slab)
+ __unfreeze_partials(s, partial_slab);
+}
+
+static void unfreeze_partials_cpu(struct kmem_cache *s,
+ struct kmem_cache_cpu *c)
+{
+ struct slab *partial_slab;
+
+ partial_slab = slub_percpu_partial(c);
+ c->partial = NULL;
+
+ if (partial_slab)
+ __unfreeze_partials(s, partial_slab);
+}
+
+/*
+ * Put a slab that was just frozen (in __slab_free|get_partial_node) into a
+ * partial slab slot if available.
+ *
+ * If we did not find a slot then simply move all the partials to the
+ * per node partial list.
+ */
+static void put_cpu_partial(struct kmem_cache *s, struct slab *slab, int drain)
+{
+ struct slab *oldslab;
+ struct slab *slab_to_unfreeze = NULL;
+ unsigned long flags;
+ int slabs = 0;
+
+ local_lock_irqsave(&s->cpu_slab->lock, flags);
+
+ oldslab = this_cpu_read(s->cpu_slab->partial);
+
+ if (oldslab) {
+ if (drain && oldslab->slabs >= s->cpu_partial_slabs) {
+ /*
+ * Partial array is full. Move the existing set to the
+ * per node partial list. Postpone the actual unfreezing
+ * outside of the critical section.
+ */
+ slab_to_unfreeze = oldslab;
+ oldslab = NULL;
+ } else {
+ slabs = oldslab->slabs;
+ }
+ }
+
+ slabs++;
+
+ slab->slabs = slabs;
+ slab->next = oldslab;
+
+ this_cpu_write(s->cpu_slab->partial, slab);
+
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+
+ if (slab_to_unfreeze) {
+ __unfreeze_partials(s, slab_to_unfreeze);
+ stat(s, CPU_PARTIAL_DRAIN);
+ }
+}
+
+#else /* CONFIG_SLUB_CPU_PARTIAL */
+
+static inline void unfreeze_partials(struct kmem_cache *s) { }
+static inline void unfreeze_partials_cpu(struct kmem_cache *s,
+ struct kmem_cache_cpu *c) { }
+
+#endif /* CONFIG_SLUB_CPU_PARTIAL */
+
+static inline void flush_slab(struct kmem_cache *s, struct kmem_cache_cpu *c)
+{
+ unsigned long flags;
+ struct slab *slab;
+ void *freelist;
+
+ local_lock_irqsave(&s->cpu_slab->lock, flags);
+
+ slab = c->slab;
+ freelist = c->freelist;
+
+ c->slab = NULL;
+ c->freelist = NULL;
+ c->tid = next_tid(c->tid);
+
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+
+ if (slab) {
+ deactivate_slab(s, slab, freelist);
+ stat(s, CPUSLAB_FLUSH);
+ }
+}
+
+static inline void __flush_cpu_slab(struct kmem_cache *s, int cpu)
+{
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+ void *freelist = c->freelist;
+ struct slab *slab = c->slab;
+
+ c->slab = NULL;
+ c->freelist = NULL;
+ c->tid = next_tid(c->tid);
+
+ if (slab) {
+ deactivate_slab(s, slab, freelist);
+ stat(s, CPUSLAB_FLUSH);
+ }
+
+ unfreeze_partials_cpu(s, c);
+}
+
+struct slub_flush_work {
+ struct work_struct work;
+ struct kmem_cache *s;
+ bool skip;
+};
+
+/*
+ * Flush cpu slab.
+ *
+ * Called from CPU work handler with migration disabled.
+ */
+static void flush_cpu_slab(struct work_struct *w)
+{
+ struct kmem_cache *s;
+ struct kmem_cache_cpu *c;
+ struct slub_flush_work *sfw;
+
+ sfw = container_of(w, struct slub_flush_work, work);
+
+ s = sfw->s;
+ c = this_cpu_ptr(s->cpu_slab);
+
+ if (c->slab)
+ flush_slab(s, c);
+
+ unfreeze_partials(s);
+}
+
+static bool has_cpu_slab(int cpu, struct kmem_cache *s)
+{
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab, cpu);
+
+ return c->slab || slub_percpu_partial(c);
+}
+
+static DEFINE_MUTEX(flush_lock);
+static DEFINE_PER_CPU(struct slub_flush_work, slub_flush);
+
+static void flush_all_cpus_locked(struct kmem_cache *s)
+{
+ struct slub_flush_work *sfw;
+ unsigned int cpu;
+
+ lockdep_assert_cpus_held();
+ mutex_lock(&flush_lock);
+
+ for_each_online_cpu(cpu) {
+ sfw = &per_cpu(slub_flush, cpu);
+ if (!has_cpu_slab(cpu, s)) {
+ sfw->skip = true;
+ continue;
+ }
+ INIT_WORK(&sfw->work, flush_cpu_slab);
+ sfw->skip = false;
+ sfw->s = s;
+ queue_work_on(cpu, flushwq, &sfw->work);
+ }
+
+ for_each_online_cpu(cpu) {
+ sfw = &per_cpu(slub_flush, cpu);
+ if (sfw->skip)
+ continue;
+ flush_work(&sfw->work);
+ }
+
+ mutex_unlock(&flush_lock);
+}
+
+static void flush_all(struct kmem_cache *s)
+{
+ cpus_read_lock();
+ flush_all_cpus_locked(s);
+ cpus_read_unlock();
+}
+
+/*
+ * Use the cpu notifier to insure that the cpu slabs are flushed when
+ * necessary.
+ */
+static int slub_cpu_dead(unsigned int cpu)
+{
+ struct kmem_cache *s;
+
+ mutex_lock(&slab_mutex);
+ list_for_each_entry(s, &slab_caches, list)
+ __flush_cpu_slab(s, cpu);
+ mutex_unlock(&slab_mutex);
+ return 0;
+}
+
+/*
+ * Check if the objects in a per cpu structure fit numa
+ * locality expectations.
+ */
+static inline int node_match(struct slab *slab, int node)
+{
+#ifdef CONFIG_NUMA
+ if (node != NUMA_NO_NODE && slab_nid(slab) != node)
+ return 0;
+#endif
+ return 1;
+}
+
+#ifdef CONFIG_SLUB_DEBUG
+static int count_free(struct slab *slab)
+{
+ return slab->objects - slab->inuse;
+}
+
+static inline unsigned long node_nr_objs(struct kmem_cache_node *n)
+{
+ return atomic_long_read(&n->total_objects);
+}
+
+/* Supports checking bulk free of a constructed freelist */
+static noinline void free_debug_processing(
+ struct kmem_cache *s, struct slab *slab,
+ void *head, void *tail, int bulk_cnt,
+ unsigned long addr)
+{
+ struct kmem_cache_node *n = get_node(s, slab_nid(slab));
+ struct slab *slab_free = NULL;
+ void *object = head;
+ int cnt = 0;
+ unsigned long flags;
+ bool checks_ok = false;
+ depot_stack_handle_t handle = 0;
+
+ if (s->flags & SLAB_STORE_USER)
+ handle = set_track_prepare();
+
+ spin_lock_irqsave(&n->list_lock, flags);
+
+ if (s->flags & SLAB_CONSISTENCY_CHECKS) {
+ if (!check_slab(s, slab))
+ goto out;
+ }
+
+ if (slab->inuse < bulk_cnt) {
+ slab_err(s, slab, "Slab has %d allocated objects but %d are to be freed\n",
+ slab->inuse, bulk_cnt);
+ goto out;
+ }
+
+next_object:
+
+ if (++cnt > bulk_cnt)
+ goto out_cnt;
+
+ if (s->flags & SLAB_CONSISTENCY_CHECKS) {
+ if (!free_consistency_checks(s, slab, object, addr))
+ goto out;
+ }
+
+ if (s->flags & SLAB_STORE_USER)
+ set_track_update(s, object, TRACK_FREE, addr, handle);
+ trace(s, slab, object, 0);
+ /* Freepointer not overwritten by init_object(), SLAB_POISON moved it */
+ init_object(s, object, SLUB_RED_INACTIVE);
+
+ /* Reached end of constructed freelist yet? */
+ if (object != tail) {
+ object = get_freepointer(s, object);
+ goto next_object;
+ }
+ checks_ok = true;
+
+out_cnt:
+ if (cnt != bulk_cnt)
+ slab_err(s, slab, "Bulk free expected %d objects but found %d\n",
+ bulk_cnt, cnt);
+
+out:
+ if (checks_ok) {
+ void *prior = slab->freelist;
+
+ /* Perform the actual freeing while we still hold the locks */
+ slab->inuse -= cnt;
+ set_freepointer(s, tail, prior);
+ slab->freelist = head;
+
+ /*
+ * If the slab is empty, and node's partial list is full,
+ * it should be discarded anyway no matter it's on full or
+ * partial list.
+ */
+ if (slab->inuse == 0 && n->nr_partial >= s->min_partial)
+ slab_free = slab;
+
+ if (!prior) {
+ /* was on full list */
+ remove_full(s, n, slab);
+ if (!slab_free) {
+ add_partial(n, slab, DEACTIVATE_TO_TAIL);
+ stat(s, FREE_ADD_PARTIAL);
+ }
+ } else if (slab_free) {
+ remove_partial(n, slab);
+ stat(s, FREE_REMOVE_PARTIAL);
+ }
+ }
+
+ if (slab_free) {
+ /*
+ * Update the counters while still holding n->list_lock to
+ * prevent spurious validation warnings
+ */
+ dec_slabs_node(s, slab_nid(slab_free), slab_free->objects);
+ }
+
+ spin_unlock_irqrestore(&n->list_lock, flags);
+
+ if (!checks_ok)
+ slab_fix(s, "Object at 0x%p not freed", object);
+
+ if (slab_free) {
+ stat(s, FREE_SLAB);
+ free_slab(s, slab_free);
+ }
+}
+#endif /* CONFIG_SLUB_DEBUG */
+
+#if defined(CONFIG_SLUB_DEBUG) || defined(CONFIG_SYSFS)
+static unsigned long count_partial(struct kmem_cache_node *n,
+ int (*get_count)(struct slab *))
+{
+ unsigned long flags;
+ unsigned long x = 0;
+ struct slab *slab;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry(slab, &n->partial, slab_list)
+ x += get_count(slab);
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ return x;
+}
+#endif /* CONFIG_SLUB_DEBUG || CONFIG_SYSFS */
+
+static noinline void
+slab_out_of_memory(struct kmem_cache *s, gfp_t gfpflags, int nid)
+{
+#ifdef CONFIG_SLUB_DEBUG
+ static DEFINE_RATELIMIT_STATE(slub_oom_rs, DEFAULT_RATELIMIT_INTERVAL,
+ DEFAULT_RATELIMIT_BURST);
+ int node;
+ struct kmem_cache_node *n;
+
+ if ((gfpflags & __GFP_NOWARN) || !__ratelimit(&slub_oom_rs))
+ return;
+
+ pr_warn("SLUB: Unable to allocate memory on node %d, gfp=%#x(%pGg)\n",
+ nid, gfpflags, &gfpflags);
+ pr_warn(" cache: %s, object size: %u, buffer size: %u, default order: %u, min order: %u\n",
+ s->name, s->object_size, s->size, oo_order(s->oo),
+ oo_order(s->min));
+
+ if (oo_order(s->min) > get_order(s->object_size))
+ pr_warn(" %s debugging increased min order, use slub_debug=O to disable.\n",
+ s->name);
+
+ for_each_kmem_cache_node(s, node, n) {
+ unsigned long nr_slabs;
+ unsigned long nr_objs;
+ unsigned long nr_free;
+
+ nr_free = count_partial(n, count_free);
+ nr_slabs = node_nr_slabs(n);
+ nr_objs = node_nr_objs(n);
+
+ pr_warn(" node %d: slabs: %ld, objs: %ld, free: %ld\n",
+ node, nr_slabs, nr_objs, nr_free);
+ }
+#endif
+}
+
+static inline bool pfmemalloc_match(struct slab *slab, gfp_t gfpflags)
+{
+ if (unlikely(slab_test_pfmemalloc(slab)))
+ return gfp_pfmemalloc_allowed(gfpflags);
+
+ return true;
+}
+
+/*
+ * Check the slab->freelist and either transfer the freelist to the
+ * per cpu freelist or deactivate the slab.
+ *
+ * The slab is still frozen if the return value is not NULL.
+ *
+ * If this function returns NULL then the slab has been unfrozen.
+ */
+static inline void *get_freelist(struct kmem_cache *s, struct slab *slab)
+{
+ struct slab new;
+ unsigned long counters;
+ void *freelist;
+
+ lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
+
+ do {
+ freelist = slab->freelist;
+ counters = slab->counters;
+
+ new.counters = counters;
+ VM_BUG_ON(!new.frozen);
+
+ new.inuse = slab->objects;
+ new.frozen = freelist != NULL;
+
+ } while (!__cmpxchg_double_slab(s, slab,
+ freelist, counters,
+ NULL, new.counters,
+ "get_freelist"));
+
+ return freelist;
+}
+
+/*
+ * Slow path. The lockless freelist is empty or we need to perform
+ * debugging duties.
+ *
+ * Processing is still very fast if new objects have been freed to the
+ * regular freelist. In that case we simply take over the regular freelist
+ * as the lockless freelist and zap the regular freelist.
+ *
+ * If that is not working then we fall back to the partial lists. We take the
+ * first element of the freelist as the object to allocate now and move the
+ * rest of the freelist to the lockless freelist.
+ *
+ * And if we were unable to get a new slab from the partial slab lists then
+ * we need to allocate a new slab. This is the slowest path since it involves
+ * a call to the page allocator and the setup of a new slab.
+ *
+ * Version of __slab_alloc to use when we know that preemption is
+ * already disabled (which is the case for bulk allocation).
+ */
+static void *___slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
+{
+ void *freelist;
+ struct slab *slab;
+ unsigned long flags;
+ struct partial_context pc;
+
+ stat(s, ALLOC_SLOWPATH);
+
+reread_slab:
+
+ slab = READ_ONCE(c->slab);
+ if (!slab) {
+ /*
+ * if the node is not online or has no normal memory, just
+ * ignore the node constraint
+ */
+ if (unlikely(node != NUMA_NO_NODE &&
+ !node_isset(node, slab_nodes)))
+ node = NUMA_NO_NODE;
+ goto new_slab;
+ }
+redo:
+
+ if (unlikely(!node_match(slab, node))) {
+ /*
+ * same as above but node_match() being false already
+ * implies node != NUMA_NO_NODE
+ */
+ if (!node_isset(node, slab_nodes)) {
+ node = NUMA_NO_NODE;
+ } else {
+ stat(s, ALLOC_NODE_MISMATCH);
+ goto deactivate_slab;
+ }
+ }
+
+ /*
+ * By rights, we should be searching for a slab page that was
+ * PFMEMALLOC but right now, we are losing the pfmemalloc
+ * information when the page leaves the per-cpu allocator
+ */
+ if (unlikely(!pfmemalloc_match(slab, gfpflags)))
+ goto deactivate_slab;
+
+ /* must check again c->slab in case we got preempted and it changed */
+ local_lock_irqsave(&s->cpu_slab->lock, flags);
+ if (unlikely(slab != c->slab)) {
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ goto reread_slab;
+ }
+ freelist = c->freelist;
+ if (freelist)
+ goto load_freelist;
+
+ freelist = get_freelist(s, slab);
+
+ if (!freelist) {
+ c->slab = NULL;
+ c->tid = next_tid(c->tid);
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ stat(s, DEACTIVATE_BYPASS);
+ goto new_slab;
+ }
+
+ stat(s, ALLOC_REFILL);
+
+load_freelist:
+
+ lockdep_assert_held(this_cpu_ptr(&s->cpu_slab->lock));
+
+ /*
+ * freelist is pointing to the list of objects to be used.
+ * slab is pointing to the slab from which the objects are obtained.
+ * That slab must be frozen for per cpu allocations to work.
+ */
+ VM_BUG_ON(!c->slab->frozen);
+ c->freelist = get_freepointer(s, freelist);
+ c->tid = next_tid(c->tid);
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ return freelist;
+
+deactivate_slab:
+
+ local_lock_irqsave(&s->cpu_slab->lock, flags);
+ if (slab != c->slab) {
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ goto reread_slab;
+ }
+ freelist = c->freelist;
+ c->slab = NULL;
+ c->freelist = NULL;
+ c->tid = next_tid(c->tid);
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ deactivate_slab(s, slab, freelist);
+
+new_slab:
+
+ if (slub_percpu_partial(c)) {
+ local_lock_irqsave(&s->cpu_slab->lock, flags);
+ if (unlikely(c->slab)) {
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ goto reread_slab;
+ }
+ if (unlikely(!slub_percpu_partial(c))) {
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ /* we were preempted and partial list got empty */
+ goto new_objects;
+ }
+
+ slab = c->slab = slub_percpu_partial(c);
+ slub_set_percpu_partial(c, slab);
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+ stat(s, CPU_PARTIAL_ALLOC);
+ goto redo;
+ }
+
+new_objects:
+
+ pc.flags = gfpflags;
+ pc.slab = &slab;
+ pc.orig_size = orig_size;
+ freelist = get_partial(s, node, &pc);
+ if (freelist)
+ goto check_new_slab;
+
+ slub_put_cpu_ptr(s->cpu_slab);
+ slab = new_slab(s, gfpflags, node);
+ c = slub_get_cpu_ptr(s->cpu_slab);
+
+ if (unlikely(!slab)) {
+ slab_out_of_memory(s, gfpflags, node);
+ return NULL;
+ }
+
+ stat(s, ALLOC_SLAB);
+
+ if (kmem_cache_debug(s)) {
+ freelist = alloc_single_from_new_slab(s, slab, orig_size);
+
+ if (unlikely(!freelist))
+ goto new_objects;
+
+ if (s->flags & SLAB_STORE_USER)
+ set_track(s, freelist, TRACK_ALLOC, addr);
+
+ return freelist;
+ }
+
+ /*
+ * No other reference to the slab yet so we can
+ * muck around with it freely without cmpxchg
+ */
+ freelist = slab->freelist;
+ slab->freelist = NULL;
+ slab->inuse = slab->objects;
+ slab->frozen = 1;
+
+ inc_slabs_node(s, slab_nid(slab), slab->objects);
+
+check_new_slab:
+
+ if (kmem_cache_debug(s)) {
+ /*
+ * For debug caches here we had to go through
+ * alloc_single_from_partial() so just store the tracking info
+ * and return the object
+ */
+ if (s->flags & SLAB_STORE_USER)
+ set_track(s, freelist, TRACK_ALLOC, addr);
+
+ return freelist;
+ }
+
+ if (unlikely(!pfmemalloc_match(slab, gfpflags))) {
+ /*
+ * For !pfmemalloc_match() case we don't load freelist so that
+ * we don't make further mismatched allocations easier.
+ */
+ deactivate_slab(s, slab, get_freepointer(s, freelist));
+ return freelist;
+ }
+
+retry_load_slab:
+
+ local_lock_irqsave(&s->cpu_slab->lock, flags);
+ if (unlikely(c->slab)) {
+ void *flush_freelist = c->freelist;
+ struct slab *flush_slab = c->slab;
+
+ c->slab = NULL;
+ c->freelist = NULL;
+ c->tid = next_tid(c->tid);
+
+ local_unlock_irqrestore(&s->cpu_slab->lock, flags);
+
+ deactivate_slab(s, flush_slab, flush_freelist);
+
+ stat(s, CPUSLAB_FLUSH);
+
+ goto retry_load_slab;
+ }
+ c->slab = slab;
+
+ goto load_freelist;
+}
+
+/*
+ * A wrapper for ___slab_alloc() for contexts where preemption is not yet
+ * disabled. Compensates for possible cpu changes by refetching the per cpu area
+ * pointer.
+ */
+static void *__slab_alloc(struct kmem_cache *s, gfp_t gfpflags, int node,
+ unsigned long addr, struct kmem_cache_cpu *c, unsigned int orig_size)
+{
+ void *p;
+
+#ifdef CONFIG_PREEMPT_COUNT
+ /*
+ * We may have been preempted and rescheduled on a different
+ * cpu before disabling preemption. Need to reload cpu area
+ * pointer.
+ */
+ c = slub_get_cpu_ptr(s->cpu_slab);
+#endif
+
+ p = ___slab_alloc(s, gfpflags, node, addr, c, orig_size);
+#ifdef CONFIG_PREEMPT_COUNT
+ slub_put_cpu_ptr(s->cpu_slab);
+#endif
+ return p;
+}
+
+/*
+ * If the object has been wiped upon free, make sure it's fully initialized by
+ * zeroing out freelist pointer.
+ */
+static __always_inline void maybe_wipe_obj_freeptr(struct kmem_cache *s,
+ void *obj)
+{
+ if (unlikely(slab_want_init_on_free(s)) && obj)
+ memset((void *)((char *)kasan_reset_tag(obj) + s->offset),
+ 0, sizeof(void *));
+}
+
+/*
+ * Inlined fastpath so that allocation functions (kmalloc, kmem_cache_alloc)
+ * have the fastpath folded into their functions. So no function call
+ * overhead for requests that can be satisfied on the fastpath.
+ *
+ * The fastpath works by first checking if the lockless freelist can be used.
+ * If not then __slab_alloc is called for slow processing.
+ *
+ * Otherwise we can simply pick the next object from the lockless free list.
+ */
+static __always_inline void *slab_alloc_node(struct kmem_cache *s, struct list_lru *lru,
+ gfp_t gfpflags, int node, unsigned long addr, size_t orig_size)
+{
+ void *object;
+ struct kmem_cache_cpu *c;
+ struct slab *slab;
+ unsigned long tid;
+ struct obj_cgroup *objcg = NULL;
+ bool init = false;
+
+ s = slab_pre_alloc_hook(s, lru, &objcg, 1, gfpflags);
+ if (!s)
+ return NULL;
+
+ object = kfence_alloc(s, orig_size, gfpflags);
+ if (unlikely(object))
+ goto out;
+
+redo:
+ /*
+ * Must read kmem_cache cpu data via this cpu ptr. Preemption is
+ * enabled. We may switch back and forth between cpus while
+ * reading from one cpu area. That does not matter as long
+ * as we end up on the original cpu again when doing the cmpxchg.
+ *
+ * We must guarantee that tid and kmem_cache_cpu are retrieved on the
+ * same cpu. We read first the kmem_cache_cpu pointer and use it to read
+ * the tid. If we are preempted and switched to another cpu between the
+ * two reads, it's OK as the two are still associated with the same cpu
+ * and cmpxchg later will validate the cpu.
+ */
+ c = raw_cpu_ptr(s->cpu_slab);
+ tid = READ_ONCE(c->tid);
+
+ /*
+ * Irqless object alloc/free algorithm used here depends on sequence
+ * of fetching cpu_slab's data. tid should be fetched before anything
+ * on c to guarantee that object and slab associated with previous tid
+ * won't be used with current tid. If we fetch tid first, object and
+ * slab could be one associated with next tid and our alloc/free
+ * request will be failed. In this case, we will retry. So, no problem.
+ */
+ barrier();
+
+ /*
+ * The transaction ids are globally unique per cpu and per operation on
+ * a per cpu queue. Thus they can be guarantee that the cmpxchg_double
+ * occurs on the right processor and that there was no operation on the
+ * linked list in between.
+ */
+
+ object = c->freelist;
+ slab = c->slab;
+
+ if (!USE_LOCKLESS_FAST_PATH() ||
+ unlikely(!object || !slab || !node_match(slab, node))) {
+ object = __slab_alloc(s, gfpflags, node, addr, c, orig_size);
+ } else {
+ void *next_object = get_freepointer_safe(s, object);
+
+ /*
+ * The cmpxchg will only match if there was no additional
+ * operation and if we are on the right processor.
+ *
+ * The cmpxchg does the following atomically (without lock
+ * semantics!)
+ * 1. Relocate first pointer to the current per cpu area.
+ * 2. Verify that tid and freelist have not been changed
+ * 3. If they were not changed replace tid and freelist
+ *
+ * Since this is without lock semantics the protection is only
+ * against code executing on this cpu *not* from access by
+ * other cpus.
+ */
+ if (unlikely(!this_cpu_cmpxchg_double(
+ s->cpu_slab->freelist, s->cpu_slab->tid,
+ object, tid,
+ next_object, next_tid(tid)))) {
+
+ note_cmpxchg_failure("slab_alloc", s, tid);
+ goto redo;
+ }
+ prefetch_freepointer(s, next_object);
+ stat(s, ALLOC_FASTPATH);
+ }
+
+ maybe_wipe_obj_freeptr(s, object);
+ init = slab_want_init_on_alloc(gfpflags, s);
+
+out:
+ slab_post_alloc_hook(s, objcg, gfpflags, 1, &object, init);
+
+ return object;
+}
+
+static __always_inline void *slab_alloc(struct kmem_cache *s, struct list_lru *lru,
+ gfp_t gfpflags, unsigned long addr, size_t orig_size)
+{
+ return slab_alloc_node(s, lru, gfpflags, NUMA_NO_NODE, addr, orig_size);
+}
+
+static __always_inline
+void *__kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
+ gfp_t gfpflags)
+{
+ void *ret = slab_alloc(s, lru, gfpflags, _RET_IP_, s->object_size);
+
+ trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, NUMA_NO_NODE);
+
+ return ret;
+}
+
+void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
+{
+ return __kmem_cache_alloc_lru(s, NULL, gfpflags);
+}
+EXPORT_SYMBOL(kmem_cache_alloc);
+
+void *kmem_cache_alloc_lru(struct kmem_cache *s, struct list_lru *lru,
+ gfp_t gfpflags)
+{
+ return __kmem_cache_alloc_lru(s, lru, gfpflags);
+}
+EXPORT_SYMBOL(kmem_cache_alloc_lru);
+
+void *__kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags,
+ int node, size_t orig_size,
+ unsigned long caller)
+{
+ return slab_alloc_node(s, NULL, gfpflags, node,
+ caller, orig_size);
+}
+
+void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
+{
+ void *ret = slab_alloc_node(s, NULL, gfpflags, node, _RET_IP_, s->object_size);
+
+ trace_kmem_cache_alloc(_RET_IP_, ret, s, gfpflags, node);
+
+ return ret;
+}
+EXPORT_SYMBOL(kmem_cache_alloc_node);
+
+/*
+ * Slow path handling. This may still be called frequently since objects
+ * have a longer lifetime than the cpu slabs in most processing loads.
+ *
+ * So we still attempt to reduce cache line usage. Just take the slab
+ * lock and free the item. If there is no additional partial slab
+ * handling required then we can return immediately.
+ */
+static void __slab_free(struct kmem_cache *s, struct slab *slab,
+ void *head, void *tail, int cnt,
+ unsigned long addr)
+
+{
+ void *prior;
+ int was_frozen;
+ struct slab new;
+ unsigned long counters;
+ struct kmem_cache_node *n = NULL;
+ unsigned long flags;
+
+ stat(s, FREE_SLOWPATH);
+
+ if (kfence_free(head))
+ return;
+
+ if (kmem_cache_debug(s)) {
+ free_debug_processing(s, slab, head, tail, cnt, addr);
+ return;
+ }
+
+ do {
+ if (unlikely(n)) {
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ n = NULL;
+ }
+ prior = slab->freelist;
+ counters = slab->counters;
+ set_freepointer(s, tail, prior);
+ new.counters = counters;
+ was_frozen = new.frozen;
+ new.inuse -= cnt;
+ if ((!new.inuse || !prior) && !was_frozen) {
+
+ if (kmem_cache_has_cpu_partial(s) && !prior) {
+
+ /*
+ * Slab was on no list before and will be
+ * partially empty
+ * We can defer the list move and instead
+ * freeze it.
+ */
+ new.frozen = 1;
+
+ } else { /* Needs to be taken off a list */
+
+ n = get_node(s, slab_nid(slab));
+ /*
+ * Speculatively acquire the list_lock.
+ * If the cmpxchg does not succeed then we may
+ * drop the list_lock without any processing.
+ *
+ * Otherwise the list_lock will synchronize with
+ * other processors updating the list of slabs.
+ */
+ spin_lock_irqsave(&n->list_lock, flags);
+
+ }
+ }
+
+ } while (!cmpxchg_double_slab(s, slab,
+ prior, counters,
+ head, new.counters,
+ "__slab_free"));
+
+ if (likely(!n)) {
+
+ if (likely(was_frozen)) {
+ /*
+ * The list lock was not taken therefore no list
+ * activity can be necessary.
+ */
+ stat(s, FREE_FROZEN);
+ } else if (new.frozen) {
+ /*
+ * If we just froze the slab then put it onto the
+ * per cpu partial list.
+ */
+ put_cpu_partial(s, slab, 1);
+ stat(s, CPU_PARTIAL_FREE);
+ }
+
+ return;
+ }
+
+ if (unlikely(!new.inuse && n->nr_partial >= s->min_partial))
+ goto slab_empty;
+
+ /*
+ * Objects left in the slab. If it was not on the partial list before
+ * then add it.
+ */
+ if (!kmem_cache_has_cpu_partial(s) && unlikely(!prior)) {
+ remove_full(s, n, slab);
+ add_partial(n, slab, DEACTIVATE_TO_TAIL);
+ stat(s, FREE_ADD_PARTIAL);
+ }
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ return;
+
+slab_empty:
+ if (prior) {
+ /*
+ * Slab on the partial list.
+ */
+ remove_partial(n, slab);
+ stat(s, FREE_REMOVE_PARTIAL);
+ } else {
+ /* Slab must be on the full list */
+ remove_full(s, n, slab);
+ }
+
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ stat(s, FREE_SLAB);
+ discard_slab(s, slab);
+}
+
+/*
+ * Fastpath with forced inlining to produce a kfree and kmem_cache_free that
+ * can perform fastpath freeing without additional function calls.
+ *
+ * The fastpath is only possible if we are freeing to the current cpu slab
+ * of this processor. This typically the case if we have just allocated
+ * the item before.
+ *
+ * If fastpath is not possible then fall back to __slab_free where we deal
+ * with all sorts of special processing.
+ *
+ * Bulk free of a freelist with several objects (all pointing to the
+ * same slab) possible by specifying head and tail ptr, plus objects
+ * count (cnt). Bulk free indicated by tail pointer being set.
+ */
+static __always_inline void do_slab_free(struct kmem_cache *s,
+ struct slab *slab, void *head, void *tail,
+ int cnt, unsigned long addr)
+{
+ void *tail_obj = tail ? : head;
+ struct kmem_cache_cpu *c;
+ unsigned long tid;
+ void **freelist;
+
+redo:
+ /*
+ * Determine the currently cpus per cpu slab.
+ * The cpu may change afterward. However that does not matter since
+ * data is retrieved via this pointer. If we are on the same cpu
+ * during the cmpxchg then the free will succeed.
+ */
+ c = raw_cpu_ptr(s->cpu_slab);
+ tid = READ_ONCE(c->tid);
+
+ /* Same with comment on barrier() in slab_alloc_node() */
+ barrier();
+
+ if (unlikely(slab != c->slab)) {
+ __slab_free(s, slab, head, tail_obj, cnt, addr);
+ return;
+ }
+
+ if (USE_LOCKLESS_FAST_PATH()) {
+ freelist = READ_ONCE(c->freelist);
+
+ set_freepointer(s, tail_obj, freelist);
+
+ if (unlikely(!this_cpu_cmpxchg_double(
+ s->cpu_slab->freelist, s->cpu_slab->tid,
+ freelist, tid,
+ head, next_tid(tid)))) {
+
+ note_cmpxchg_failure("slab_free", s, tid);
+ goto redo;
+ }
+ } else {
+ /* Update the free list under the local lock */
+ local_lock(&s->cpu_slab->lock);
+ c = this_cpu_ptr(s->cpu_slab);
+ if (unlikely(slab != c->slab)) {
+ local_unlock(&s->cpu_slab->lock);
+ goto redo;
+ }
+ tid = c->tid;
+ freelist = c->freelist;
+
+ set_freepointer(s, tail_obj, freelist);
+ c->freelist = head;
+ c->tid = next_tid(tid);
+
+ local_unlock(&s->cpu_slab->lock);
+ }
+ stat(s, FREE_FASTPATH);
+}
+
+static __always_inline void slab_free(struct kmem_cache *s, struct slab *slab,
+ void *head, void *tail, void **p, int cnt,
+ unsigned long addr)
+{
+ memcg_slab_free_hook(s, slab, p, cnt);
+ /*
+ * With KASAN enabled slab_free_freelist_hook modifies the freelist
+ * to remove objects, whose reuse must be delayed.
+ */
+ if (slab_free_freelist_hook(s, &head, &tail, &cnt))
+ do_slab_free(s, slab, head, tail, cnt, addr);
+}
+
+#ifdef CONFIG_KASAN_GENERIC
+void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr)
+{
+ do_slab_free(cache, virt_to_slab(x), x, NULL, 1, addr);
+}
+#endif
+
+void __kmem_cache_free(struct kmem_cache *s, void *x, unsigned long caller)
+{
+ slab_free(s, virt_to_slab(x), x, NULL, &x, 1, caller);
+}
+
+void kmem_cache_free(struct kmem_cache *s, void *x)
+{
+ s = cache_from_obj(s, x);
+ if (!s)
+ return;
+ trace_kmem_cache_free(_RET_IP_, x, s);
+ slab_free(s, virt_to_slab(x), x, NULL, &x, 1, _RET_IP_);
+}
+EXPORT_SYMBOL(kmem_cache_free);
+
+struct detached_freelist {
+ struct slab *slab;
+ void *tail;
+ void *freelist;
+ int cnt;
+ struct kmem_cache *s;
+};
+
+/*
+ * This function progressively scans the array with free objects (with
+ * a limited look ahead) and extract objects belonging to the same
+ * slab. It builds a detached freelist directly within the given
+ * slab/objects. This can happen without any need for
+ * synchronization, because the objects are owned by running process.
+ * The freelist is build up as a single linked list in the objects.
+ * The idea is, that this detached freelist can then be bulk
+ * transferred to the real freelist(s), but only requiring a single
+ * synchronization primitive. Look ahead in the array is limited due
+ * to performance reasons.
+ */
+static inline
+int build_detached_freelist(struct kmem_cache *s, size_t size,
+ void **p, struct detached_freelist *df)
+{
+ int lookahead = 3;
+ void *object;
+ struct folio *folio;
+ size_t same;
+
+ object = p[--size];
+ folio = virt_to_folio(object);
+ if (!s) {
+ /* Handle kalloc'ed objects */
+ if (unlikely(!folio_test_slab(folio))) {
+ free_large_kmalloc(folio, object);
+ df->slab = NULL;
+ return size;
+ }
+ /* Derive kmem_cache from object */
+ df->slab = folio_slab(folio);
+ df->s = df->slab->slab_cache;
+ } else {
+ df->slab = folio_slab(folio);
+ df->s = cache_from_obj(s, object); /* Support for memcg */
+ }
+
+ /* Start new detached freelist */
+ df->tail = object;
+ df->freelist = object;
+ df->cnt = 1;
+
+ if (is_kfence_address(object))
+ return size;
+
+ set_freepointer(df->s, object, NULL);
+
+ same = size;
+ while (size) {
+ object = p[--size];
+ /* df->slab is always set at this point */
+ if (df->slab == virt_to_slab(object)) {
+ /* Opportunity build freelist */
+ set_freepointer(df->s, object, df->freelist);
+ df->freelist = object;
+ df->cnt++;
+ same--;
+ if (size != same)
+ swap(p[size], p[same]);
+ continue;
+ }
+
+ /* Limit look ahead search */
+ if (!--lookahead)
+ break;
+ }
+
+ return same;
+}
+
+/* Note that interrupts must be enabled when calling this function. */
+void kmem_cache_free_bulk(struct kmem_cache *s, size_t size, void **p)
+{
+ if (!size)
+ return;
+
+ do {
+ struct detached_freelist df;
+
+ size = build_detached_freelist(s, size, p, &df);
+ if (!df.slab)
+ continue;
+
+ slab_free(df.s, df.slab, df.freelist, df.tail, &p[size], df.cnt,
+ _RET_IP_);
+ } while (likely(size));
+}
+EXPORT_SYMBOL(kmem_cache_free_bulk);
+
+/* Note that interrupts must be enabled when calling this function. */
+int kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t size,
+ void **p)
+{
+ struct kmem_cache_cpu *c;
+ int i;
+ struct obj_cgroup *objcg = NULL;
+
+ /* memcg and kmem_cache debug support */
+ s = slab_pre_alloc_hook(s, NULL, &objcg, size, flags);
+ if (unlikely(!s))
+ return false;
+ /*
+ * Drain objects in the per cpu slab, while disabling local
+ * IRQs, which protects against PREEMPT and interrupts
+ * handlers invoking normal fastpath.
+ */
+ c = slub_get_cpu_ptr(s->cpu_slab);
+ local_lock_irq(&s->cpu_slab->lock);
+
+ for (i = 0; i < size; i++) {
+ void *object = kfence_alloc(s, s->object_size, flags);
+
+ if (unlikely(object)) {
+ p[i] = object;
+ continue;
+ }
+
+ object = c->freelist;
+ if (unlikely(!object)) {
+ /*
+ * We may have removed an object from c->freelist using
+ * the fastpath in the previous iteration; in that case,
+ * c->tid has not been bumped yet.
+ * Since ___slab_alloc() may reenable interrupts while
+ * allocating memory, we should bump c->tid now.
+ */
+ c->tid = next_tid(c->tid);
+
+ local_unlock_irq(&s->cpu_slab->lock);
+
+ /*
+ * Invoking slow path likely have side-effect
+ * of re-populating per CPU c->freelist
+ */
+ p[i] = ___slab_alloc(s, flags, NUMA_NO_NODE,
+ _RET_IP_, c, s->object_size);
+ if (unlikely(!p[i]))
+ goto error;
+
+ c = this_cpu_ptr(s->cpu_slab);
+ maybe_wipe_obj_freeptr(s, p[i]);
+
+ local_lock_irq(&s->cpu_slab->lock);
+
+ continue; /* goto for-loop */
+ }
+ c->freelist = get_freepointer(s, object);
+ p[i] = object;
+ maybe_wipe_obj_freeptr(s, p[i]);
+ }
+ c->tid = next_tid(c->tid);
+ local_unlock_irq(&s->cpu_slab->lock);
+ slub_put_cpu_ptr(s->cpu_slab);
+
+ /*
+ * memcg and kmem_cache debug support and memory initialization.
+ * Done outside of the IRQ disabled fastpath loop.
+ */
+ slab_post_alloc_hook(s, objcg, flags, size, p,
+ slab_want_init_on_alloc(flags, s));
+ return i;
+error:
+ slub_put_cpu_ptr(s->cpu_slab);
+ slab_post_alloc_hook(s, objcg, flags, i, p, false);
+ kmem_cache_free_bulk(s, i, p);
+ return 0;
+}
+EXPORT_SYMBOL(kmem_cache_alloc_bulk);
+
+
+/*
+ * Object placement in a slab is made very easy because we always start at
+ * offset 0. If we tune the size of the object to the alignment then we can
+ * get the required alignment by putting one properly sized object after
+ * another.
+ *
+ * Notice that the allocation order determines the sizes of the per cpu
+ * caches. Each processor has always one slab available for allocations.
+ * Increasing the allocation order reduces the number of times that slabs
+ * must be moved on and off the partial lists and is therefore a factor in
+ * locking overhead.
+ */
+
+/*
+ * Minimum / Maximum order of slab pages. This influences locking overhead
+ * and slab fragmentation. A higher order reduces the number of partial slabs
+ * and increases the number of allocations possible without having to
+ * take the list_lock.
+ */
+static unsigned int slub_min_order;
+static unsigned int slub_max_order = PAGE_ALLOC_COSTLY_ORDER;
+static unsigned int slub_min_objects;
+
+/*
+ * Calculate the order of allocation given an slab object size.
+ *
+ * The order of allocation has significant impact on performance and other
+ * system components. Generally order 0 allocations should be preferred since
+ * order 0 does not cause fragmentation in the page allocator. Larger objects
+ * be problematic to put into order 0 slabs because there may be too much
+ * unused space left. We go to a higher order if more than 1/16th of the slab
+ * would be wasted.
+ *
+ * In order to reach satisfactory performance we must ensure that a minimum
+ * number of objects is in one slab. Otherwise we may generate too much
+ * activity on the partial lists which requires taking the list_lock. This is
+ * less a concern for large slabs though which are rarely used.
+ *
+ * slub_max_order specifies the order where we begin to stop considering the
+ * number of objects in a slab as critical. If we reach slub_max_order then
+ * we try to keep the page order as low as possible. So we accept more waste
+ * of space in favor of a small page order.
+ *
+ * Higher order allocations also allow the placement of more objects in a
+ * slab and thereby reduce object handling overhead. If the user has
+ * requested a higher minimum order then we start with that one instead of
+ * the smallest order which will fit the object.
+ */
+static inline unsigned int calc_slab_order(unsigned int size,
+ unsigned int min_objects, unsigned int max_order,
+ unsigned int fract_leftover)
+{
+ unsigned int min_order = slub_min_order;
+ unsigned int order;
+
+ if (order_objects(min_order, size) > MAX_OBJS_PER_PAGE)
+ return get_order(size * MAX_OBJS_PER_PAGE) - 1;
+
+ for (order = max(min_order, (unsigned int)get_order(min_objects * size));
+ order <= max_order; order++) {
+
+ unsigned int slab_size = (unsigned int)PAGE_SIZE << order;
+ unsigned int rem;
+
+ rem = slab_size % size;
+
+ if (rem <= slab_size / fract_leftover)
+ break;
+ }
+
+ return order;
+}
+
+static inline int calculate_order(unsigned int size)
+{
+ unsigned int order;
+ unsigned int min_objects;
+ unsigned int max_objects;
+ unsigned int nr_cpus;
+
+ /*
+ * Attempt to find best configuration for a slab. This
+ * works by first attempting to generate a layout with
+ * the best configuration and backing off gradually.
+ *
+ * First we increase the acceptable waste in a slab. Then
+ * we reduce the minimum objects required in a slab.
+ */
+ min_objects = slub_min_objects;
+ if (!min_objects) {
+ /*
+ * Some architectures will only update present cpus when
+ * onlining them, so don't trust the number if it's just 1. But
+ * we also don't want to use nr_cpu_ids always, as on some other
+ * architectures, there can be many possible cpus, but never
+ * onlined. Here we compromise between trying to avoid too high
+ * order on systems that appear larger than they are, and too
+ * low order on systems that appear smaller than they are.
+ */
+ nr_cpus = num_present_cpus();
+ if (nr_cpus <= 1)
+ nr_cpus = nr_cpu_ids;
+ min_objects = 4 * (fls(nr_cpus) + 1);
+ }
+ max_objects = order_objects(slub_max_order, size);
+ min_objects = min(min_objects, max_objects);
+
+ while (min_objects > 1) {
+ unsigned int fraction;
+
+ fraction = 16;
+ while (fraction >= 4) {
+ order = calc_slab_order(size, min_objects,
+ slub_max_order, fraction);
+ if (order <= slub_max_order)
+ return order;
+ fraction /= 2;
+ }
+ min_objects--;
+ }
+
+ /*
+ * We were unable to place multiple objects in a slab. Now
+ * lets see if we can place a single object there.
+ */
+ order = calc_slab_order(size, 1, slub_max_order, 1);
+ if (order <= slub_max_order)
+ return order;
+
+ /*
+ * Doh this slab cannot be placed using slub_max_order.
+ */
+ order = calc_slab_order(size, 1, MAX_ORDER, 1);
+ if (order < MAX_ORDER)
+ return order;
+ return -ENOSYS;
+}
+
+static void
+init_kmem_cache_node(struct kmem_cache_node *n)
+{
+ n->nr_partial = 0;
+ spin_lock_init(&n->list_lock);
+ INIT_LIST_HEAD(&n->partial);
+#ifdef CONFIG_SLUB_DEBUG
+ atomic_long_set(&n->nr_slabs, 0);
+ atomic_long_set(&n->total_objects, 0);
+ INIT_LIST_HEAD(&n->full);
+#endif
+}
+
+static inline int alloc_kmem_cache_cpus(struct kmem_cache *s)
+{
+ BUILD_BUG_ON(PERCPU_DYNAMIC_EARLY_SIZE <
+ KMALLOC_SHIFT_HIGH * sizeof(struct kmem_cache_cpu));
+
+ /*
+ * Must align to double word boundary for the double cmpxchg
+ * instructions to work; see __pcpu_double_call_return_bool().
+ */
+ s->cpu_slab = __alloc_percpu(sizeof(struct kmem_cache_cpu),
+ 2 * sizeof(void *));
+
+ if (!s->cpu_slab)
+ return 0;
+
+ init_kmem_cache_cpus(s);
+
+ return 1;
+}
+
+static struct kmem_cache *kmem_cache_node;
+
+/*
+ * No kmalloc_node yet so do it by hand. We know that this is the first
+ * slab on the node for this slabcache. There are no concurrent accesses
+ * possible.
+ *
+ * Note that this function only works on the kmem_cache_node
+ * when allocating for the kmem_cache_node. This is used for bootstrapping
+ * memory on a fresh node that has no slab structures yet.
+ */
+static void early_kmem_cache_node_alloc(int node)
+{
+ struct slab *slab;
+ struct kmem_cache_node *n;
+
+ BUG_ON(kmem_cache_node->size < sizeof(struct kmem_cache_node));
+
+ slab = new_slab(kmem_cache_node, GFP_NOWAIT, node);
+
+ BUG_ON(!slab);
+ inc_slabs_node(kmem_cache_node, slab_nid(slab), slab->objects);
+ if (slab_nid(slab) != node) {
+ pr_err("SLUB: Unable to allocate memory from node %d\n", node);
+ pr_err("SLUB: Allocating a useless per node structure in order to be able to continue\n");
+ }
+
+ n = slab->freelist;
+ BUG_ON(!n);
+#ifdef CONFIG_SLUB_DEBUG
+ init_object(kmem_cache_node, n, SLUB_RED_ACTIVE);
+ init_tracking(kmem_cache_node, n);
+#endif
+ n = kasan_slab_alloc(kmem_cache_node, n, GFP_KERNEL, false);
+ slab->freelist = get_freepointer(kmem_cache_node, n);
+ slab->inuse = 1;
+ kmem_cache_node->node[node] = n;
+ init_kmem_cache_node(n);
+ inc_slabs_node(kmem_cache_node, node, slab->objects);
+
+ /*
+ * No locks need to be taken here as it has just been
+ * initialized and there is no concurrent access.
+ */
+ __add_partial(n, slab, DEACTIVATE_TO_HEAD);
+}
+
+static void free_kmem_cache_nodes(struct kmem_cache *s)
+{
+ int node;
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+ s->node[node] = NULL;
+ kmem_cache_free(kmem_cache_node, n);
+ }
+}
+
+void __kmem_cache_release(struct kmem_cache *s)
+{
+ cache_random_seq_destroy(s);
+ free_percpu(s->cpu_slab);
+ free_kmem_cache_nodes(s);
+}
+
+static int init_kmem_cache_nodes(struct kmem_cache *s)
+{
+ int node;
+
+ for_each_node_mask(node, slab_nodes) {
+ struct kmem_cache_node *n;
+
+ if (slab_state == DOWN) {
+ early_kmem_cache_node_alloc(node);
+ continue;
+ }
+ n = kmem_cache_alloc_node(kmem_cache_node,
+ GFP_KERNEL, node);
+
+ if (!n) {
+ free_kmem_cache_nodes(s);
+ return 0;
+ }
+
+ init_kmem_cache_node(n);
+ s->node[node] = n;
+ }
+ return 1;
+}
+
+static void set_cpu_partial(struct kmem_cache *s)
+{
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ unsigned int nr_objects;
+
+ /*
+ * cpu_partial determined the maximum number of objects kept in the
+ * per cpu partial lists of a processor.
+ *
+ * Per cpu partial lists mainly contain slabs that just have one
+ * object freed. If they are used for allocation then they can be
+ * filled up again with minimal effort. The slab will never hit the
+ * per node partial lists and therefore no locking will be required.
+ *
+ * For backwards compatibility reasons, this is determined as number
+ * of objects, even though we now limit maximum number of pages, see
+ * slub_set_cpu_partial()
+ */
+ if (!kmem_cache_has_cpu_partial(s))
+ nr_objects = 0;
+ else if (s->size >= PAGE_SIZE)
+ nr_objects = 6;
+ else if (s->size >= 1024)
+ nr_objects = 24;
+ else if (s->size >= 256)
+ nr_objects = 52;
+ else
+ nr_objects = 120;
+
+ slub_set_cpu_partial(s, nr_objects);
+#endif
+}
+
+/*
+ * calculate_sizes() determines the order and the distribution of data within
+ * a slab object.
+ */
+static int calculate_sizes(struct kmem_cache *s)
+{
+ slab_flags_t flags = s->flags;
+ unsigned int size = s->object_size;
+ unsigned int order;
+
+ /*
+ * Round up object size to the next word boundary. We can only
+ * place the free pointer at word boundaries and this determines
+ * the possible location of the free pointer.
+ */
+ size = ALIGN(size, sizeof(void *));
+
+#ifdef CONFIG_SLUB_DEBUG
+ /*
+ * Determine if we can poison the object itself. If the user of
+ * the slab may touch the object after free or before allocation
+ * then we should never poison the object itself.
+ */
+ if ((flags & SLAB_POISON) && !(flags & SLAB_TYPESAFE_BY_RCU) &&
+ !s->ctor)
+ s->flags |= __OBJECT_POISON;
+ else
+ s->flags &= ~__OBJECT_POISON;
+
+
+ /*
+ * If we are Redzoning then check if there is some space between the
+ * end of the object and the free pointer. If not then add an
+ * additional word to have some bytes to store Redzone information.
+ */
+ if ((flags & SLAB_RED_ZONE) && size == s->object_size)
+ size += sizeof(void *);
+#endif
+
+ /*
+ * With that we have determined the number of bytes in actual use
+ * by the object and redzoning.
+ */
+ s->inuse = size;
+
+ if ((flags & (SLAB_TYPESAFE_BY_RCU | SLAB_POISON)) ||
+ ((flags & SLAB_RED_ZONE) && s->object_size < sizeof(void *)) ||
+ s->ctor) {
+ /*
+ * Relocate free pointer after the object if it is not
+ * permitted to overwrite the first word of the object on
+ * kmem_cache_free.
+ *
+ * This is the case if we do RCU, have a constructor or
+ * destructor, are poisoning the objects, or are
+ * redzoning an object smaller than sizeof(void *).
+ *
+ * The assumption that s->offset >= s->inuse means free
+ * pointer is outside of the object is used in the
+ * freeptr_outside_object() function. If that is no
+ * longer true, the function needs to be modified.
+ */
+ s->offset = size;
+ size += sizeof(void *);
+ } else {
+ /*
+ * Store freelist pointer near middle of object to keep
+ * it away from the edges of the object to avoid small
+ * sized over/underflows from neighboring allocations.
+ */
+ s->offset = ALIGN_DOWN(s->object_size / 2, sizeof(void *));
+ }
+
+#ifdef CONFIG_SLUB_DEBUG
+ if (flags & SLAB_STORE_USER) {
+ /*
+ * Need to store information about allocs and frees after
+ * the object.
+ */
+ size += 2 * sizeof(struct track);
+
+ /* Save the original kmalloc request size */
+ if (flags & SLAB_KMALLOC)
+ size += sizeof(unsigned int);
+ }
+#endif
+
+ kasan_cache_create(s, &size, &s->flags);
+#ifdef CONFIG_SLUB_DEBUG
+ if (flags & SLAB_RED_ZONE) {
+ /*
+ * Add some empty padding so that we can catch
+ * overwrites from earlier objects rather than let
+ * tracking information or the free pointer be
+ * corrupted if a user writes before the start
+ * of the object.
+ */
+ size += sizeof(void *);
+
+ s->red_left_pad = sizeof(void *);
+ s->red_left_pad = ALIGN(s->red_left_pad, s->align);
+ size += s->red_left_pad;
+ }
+#endif
+
+ /*
+ * SLUB stores one object immediately after another beginning from
+ * offset 0. In order to align the objects we have to simply size
+ * each object to conform to the alignment.
+ */
+ size = ALIGN(size, s->align);
+ s->size = size;
+ s->reciprocal_size = reciprocal_value(size);
+ order = calculate_order(size);
+
+ if ((int)order < 0)
+ return 0;
+
+ s->allocflags = 0;
+ if (order)
+ s->allocflags |= __GFP_COMP;
+
+ if (s->flags & SLAB_CACHE_DMA)
+ s->allocflags |= GFP_DMA;
+
+ if (s->flags & SLAB_CACHE_DMA32)
+ s->allocflags |= GFP_DMA32;
+
+ if (s->flags & SLAB_RECLAIM_ACCOUNT)
+ s->allocflags |= __GFP_RECLAIMABLE;
+
+ /*
+ * Determine the number of objects per slab
+ */
+ s->oo = oo_make(order, size);
+ s->min = oo_make(get_order(size), size);
+
+ return !!oo_objects(s->oo);
+}
+
+static int kmem_cache_open(struct kmem_cache *s, slab_flags_t flags)
+{
+ s->flags = kmem_cache_flags(s->size, flags, s->name);
+#ifdef CONFIG_SLAB_FREELIST_HARDENED
+ s->random = get_random_long();
+#endif
+
+ if (!calculate_sizes(s))
+ goto error;
+ if (disable_higher_order_debug) {
+ /*
+ * Disable debugging flags that store metadata if the min slab
+ * order increased.
+ */
+ if (get_order(s->size) > get_order(s->object_size)) {
+ s->flags &= ~DEBUG_METADATA_FLAGS;
+ s->offset = 0;
+ if (!calculate_sizes(s))
+ goto error;
+ }
+ }
+
+#if defined(CONFIG_HAVE_CMPXCHG_DOUBLE) && \
+ defined(CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
+ if (system_has_cmpxchg_double() && (s->flags & SLAB_NO_CMPXCHG) == 0)
+ /* Enable fast mode */
+ s->flags |= __CMPXCHG_DOUBLE;
+#endif
+
+ /*
+ * The larger the object size is, the more slabs we want on the partial
+ * list to avoid pounding the page allocator excessively.
+ */
+ s->min_partial = min_t(unsigned long, MAX_PARTIAL, ilog2(s->size) / 2);
+ s->min_partial = max_t(unsigned long, MIN_PARTIAL, s->min_partial);
+
+ set_cpu_partial(s);
+
+#ifdef CONFIG_NUMA
+ s->remote_node_defrag_ratio = 1000;
+#endif
+
+ /* Initialize the pre-computed randomized freelist if slab is up */
+ if (slab_state >= UP) {
+ if (init_cache_random_seq(s))
+ goto error;
+ }
+
+ if (!init_kmem_cache_nodes(s))
+ goto error;
+
+ if (alloc_kmem_cache_cpus(s))
+ return 0;
+
+error:
+ __kmem_cache_release(s);
+ return -EINVAL;
+}
+
+static void list_slab_objects(struct kmem_cache *s, struct slab *slab,
+ const char *text)
+{
+#ifdef CONFIG_SLUB_DEBUG
+ void *addr = slab_address(slab);
+ void *p;
+
+ slab_err(s, slab, text, s->name);
+
+ spin_lock(&object_map_lock);
+ __fill_map(object_map, s, slab);
+
+ for_each_object(p, s, addr, slab->objects) {
+
+ if (!test_bit(__obj_to_index(s, addr, p), object_map)) {
+ pr_err("Object 0x%p @offset=%tu\n", p, p - addr);
+ print_tracking(s, p);
+ }
+ }
+ spin_unlock(&object_map_lock);
+#endif
+}
+
+/*
+ * Attempt to free all partial slabs on a node.
+ * This is called from __kmem_cache_shutdown(). We must take list_lock
+ * because sysfs file might still access partial list after the shutdowning.
+ */
+static void free_partial(struct kmem_cache *s, struct kmem_cache_node *n)
+{
+ LIST_HEAD(discard);
+ struct slab *slab, *h;
+
+ BUG_ON(irqs_disabled());
+ spin_lock_irq(&n->list_lock);
+ list_for_each_entry_safe(slab, h, &n->partial, slab_list) {
+ if (!slab->inuse) {
+ remove_partial(n, slab);
+ list_add(&slab->slab_list, &discard);
+ } else {
+ list_slab_objects(s, slab,
+ "Objects remaining in %s on __kmem_cache_shutdown()");
+ }
+ }
+ spin_unlock_irq(&n->list_lock);
+
+ list_for_each_entry_safe(slab, h, &discard, slab_list)
+ discard_slab(s, slab);
+}
+
+bool __kmem_cache_empty(struct kmem_cache *s)
+{
+ int node;
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n)
+ if (n->nr_partial || slabs_node(s, node))
+ return false;
+ return true;
+}
+
+/*
+ * Release all resources used by a slab cache.
+ */
+int __kmem_cache_shutdown(struct kmem_cache *s)
+{
+ int node;
+ struct kmem_cache_node *n;
+
+ flush_all_cpus_locked(s);
+ /* Attempt to free all objects */
+ for_each_kmem_cache_node(s, node, n) {
+ free_partial(s, n);
+ if (n->nr_partial || slabs_node(s, node))
+ return 1;
+ }
+ return 0;
+}
+
+#ifdef CONFIG_PRINTK
+void __kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct slab *slab)
+{
+ void *base;
+ int __maybe_unused i;
+ unsigned int objnr;
+ void *objp;
+ void *objp0;
+ struct kmem_cache *s = slab->slab_cache;
+ struct track __maybe_unused *trackp;
+
+ kpp->kp_ptr = object;
+ kpp->kp_slab = slab;
+ kpp->kp_slab_cache = s;
+ base = slab_address(slab);
+ objp0 = kasan_reset_tag(object);
+#ifdef CONFIG_SLUB_DEBUG
+ objp = restore_red_left(s, objp0);
+#else
+ objp = objp0;
+#endif
+ objnr = obj_to_index(s, slab, objp);
+ kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp);
+ objp = base + s->size * objnr;
+ kpp->kp_objp = objp;
+ if (WARN_ON_ONCE(objp < base || objp >= base + slab->objects * s->size
+ || (objp - base) % s->size) ||
+ !(s->flags & SLAB_STORE_USER))
+ return;
+#ifdef CONFIG_SLUB_DEBUG
+ objp = fixup_red_left(s, objp);
+ trackp = get_track(s, objp, TRACK_ALLOC);
+ kpp->kp_ret = (void *)trackp->addr;
+#ifdef CONFIG_STACKDEPOT
+ {
+ depot_stack_handle_t handle;
+ unsigned long *entries;
+ unsigned int nr_entries;
+
+ handle = READ_ONCE(trackp->handle);
+ if (handle) {
+ nr_entries = stack_depot_fetch(handle, &entries);
+ for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
+ kpp->kp_stack[i] = (void *)entries[i];
+ }
+
+ trackp = get_track(s, objp, TRACK_FREE);
+ handle = READ_ONCE(trackp->handle);
+ if (handle) {
+ nr_entries = stack_depot_fetch(handle, &entries);
+ for (i = 0; i < KS_ADDRS_COUNT && i < nr_entries; i++)
+ kpp->kp_free_stack[i] = (void *)entries[i];
+ }
+ }
+#endif
+#endif
+}
+#endif
+
+/********************************************************************
+ * Kmalloc subsystem
+ *******************************************************************/
+
+static int __init setup_slub_min_order(char *str)
+{
+ get_option(&str, (int *)&slub_min_order);
+
+ return 1;
+}
+
+__setup("slub_min_order=", setup_slub_min_order);
+
+static int __init setup_slub_max_order(char *str)
+{
+ get_option(&str, (int *)&slub_max_order);
+ slub_max_order = min(slub_max_order, (unsigned int)MAX_ORDER - 1);
+
+ return 1;
+}
+
+__setup("slub_max_order=", setup_slub_max_order);
+
+static int __init setup_slub_min_objects(char *str)
+{
+ get_option(&str, (int *)&slub_min_objects);
+
+ return 1;
+}
+
+__setup("slub_min_objects=", setup_slub_min_objects);
+
+#ifdef CONFIG_HARDENED_USERCOPY
+/*
+ * Rejects incorrectly sized objects and objects that are to be copied
+ * to/from userspace but do not fall entirely within the containing slab
+ * cache's usercopy region.
+ *
+ * Returns NULL if check passes, otherwise const char * to name of cache
+ * to indicate an error.
+ */
+void __check_heap_object(const void *ptr, unsigned long n,
+ const struct slab *slab, bool to_user)
+{
+ struct kmem_cache *s;
+ unsigned int offset;
+ bool is_kfence = is_kfence_address(ptr);
+
+ ptr = kasan_reset_tag(ptr);
+
+ /* Find object and usable object size. */
+ s = slab->slab_cache;
+
+ /* Reject impossible pointers. */
+ if (ptr < slab_address(slab))
+ usercopy_abort("SLUB object not in SLUB page?!", NULL,
+ to_user, 0, n);
+
+ /* Find offset within object. */
+ if (is_kfence)
+ offset = ptr - kfence_object_start(ptr);
+ else
+ offset = (ptr - slab_address(slab)) % s->size;
+
+ /* Adjust for redzone and reject if within the redzone. */
+ if (!is_kfence && kmem_cache_debug_flags(s, SLAB_RED_ZONE)) {
+ if (offset < s->red_left_pad)
+ usercopy_abort("SLUB object in left red zone",
+ s->name, to_user, offset, n);
+ offset -= s->red_left_pad;
+ }
+
+ /* Allow address range falling entirely within usercopy region. */
+ if (offset >= s->useroffset &&
+ offset - s->useroffset <= s->usersize &&
+ n <= s->useroffset - offset + s->usersize)
+ return;
+
+ usercopy_abort("SLUB object", s->name, to_user, offset, n);
+}
+#endif /* CONFIG_HARDENED_USERCOPY */
+
+#define SHRINK_PROMOTE_MAX 32
+
+/*
+ * kmem_cache_shrink discards empty slabs and promotes the slabs filled
+ * up most to the head of the partial lists. New allocations will then
+ * fill those up and thus they can be removed from the partial lists.
+ *
+ * The slabs with the least items are placed last. This results in them
+ * being allocated from last increasing the chance that the last objects
+ * are freed in them.
+ */
+static int __kmem_cache_do_shrink(struct kmem_cache *s)
+{
+ int node;
+ int i;
+ struct kmem_cache_node *n;
+ struct slab *slab;
+ struct slab *t;
+ struct list_head discard;
+ struct list_head promote[SHRINK_PROMOTE_MAX];
+ unsigned long flags;
+ int ret = 0;
+
+ for_each_kmem_cache_node(s, node, n) {
+ INIT_LIST_HEAD(&discard);
+ for (i = 0; i < SHRINK_PROMOTE_MAX; i++)
+ INIT_LIST_HEAD(promote + i);
+
+ spin_lock_irqsave(&n->list_lock, flags);
+
+ /*
+ * Build lists of slabs to discard or promote.
+ *
+ * Note that concurrent frees may occur while we hold the
+ * list_lock. slab->inuse here is the upper limit.
+ */
+ list_for_each_entry_safe(slab, t, &n->partial, slab_list) {
+ int free = slab->objects - slab->inuse;
+
+ /* Do not reread slab->inuse */
+ barrier();
+
+ /* We do not keep full slabs on the list */
+ BUG_ON(free <= 0);
+
+ if (free == slab->objects) {
+ list_move(&slab->slab_list, &discard);
+ n->nr_partial--;
+ dec_slabs_node(s, node, slab->objects);
+ } else if (free <= SHRINK_PROMOTE_MAX)
+ list_move(&slab->slab_list, promote + free - 1);
+ }
+
+ /*
+ * Promote the slabs filled up most to the head of the
+ * partial list.
+ */
+ for (i = SHRINK_PROMOTE_MAX - 1; i >= 0; i--)
+ list_splice(promote + i, &n->partial);
+
+ spin_unlock_irqrestore(&n->list_lock, flags);
+
+ /* Release empty slabs */
+ list_for_each_entry_safe(slab, t, &discard, slab_list)
+ free_slab(s, slab);
+
+ if (slabs_node(s, node))
+ ret = 1;
+ }
+
+ return ret;
+}
+
+int __kmem_cache_shrink(struct kmem_cache *s)
+{
+ flush_all(s);
+ return __kmem_cache_do_shrink(s);
+}
+
+static int slab_mem_going_offline_callback(void *arg)
+{
+ struct kmem_cache *s;
+
+ mutex_lock(&slab_mutex);
+ list_for_each_entry(s, &slab_caches, list) {
+ flush_all_cpus_locked(s);
+ __kmem_cache_do_shrink(s);
+ }
+ mutex_unlock(&slab_mutex);
+
+ return 0;
+}
+
+static void slab_mem_offline_callback(void *arg)
+{
+ struct memory_notify *marg = arg;
+ int offline_node;
+
+ offline_node = marg->status_change_nid_normal;
+
+ /*
+ * If the node still has available memory. we need kmem_cache_node
+ * for it yet.
+ */
+ if (offline_node < 0)
+ return;
+
+ mutex_lock(&slab_mutex);
+ node_clear(offline_node, slab_nodes);
+ /*
+ * We no longer free kmem_cache_node structures here, as it would be
+ * racy with all get_node() users, and infeasible to protect them with
+ * slab_mutex.
+ */
+ mutex_unlock(&slab_mutex);
+}
+
+static int slab_mem_going_online_callback(void *arg)
+{
+ struct kmem_cache_node *n;
+ struct kmem_cache *s;
+ struct memory_notify *marg = arg;
+ int nid = marg->status_change_nid_normal;
+ int ret = 0;
+
+ /*
+ * If the node's memory is already available, then kmem_cache_node is
+ * already created. Nothing to do.
+ */
+ if (nid < 0)
+ return 0;
+
+ /*
+ * We are bringing a node online. No memory is available yet. We must
+ * allocate a kmem_cache_node structure in order to bring the node
+ * online.
+ */
+ mutex_lock(&slab_mutex);
+ list_for_each_entry(s, &slab_caches, list) {
+ /*
+ * The structure may already exist if the node was previously
+ * onlined and offlined.
+ */
+ if (get_node(s, nid))
+ continue;
+ /*
+ * XXX: kmem_cache_alloc_node will fallback to other nodes
+ * since memory is not yet available from the node that
+ * is brought up.
+ */
+ n = kmem_cache_alloc(kmem_cache_node, GFP_KERNEL);
+ if (!n) {
+ ret = -ENOMEM;
+ goto out;
+ }
+ init_kmem_cache_node(n);
+ s->node[nid] = n;
+ }
+ /*
+ * Any cache created after this point will also have kmem_cache_node
+ * initialized for the new node.
+ */
+ node_set(nid, slab_nodes);
+out:
+ mutex_unlock(&slab_mutex);
+ return ret;
+}
+
+static int slab_memory_callback(struct notifier_block *self,
+ unsigned long action, void *arg)
+{
+ int ret = 0;
+
+ switch (action) {
+ case MEM_GOING_ONLINE:
+ ret = slab_mem_going_online_callback(arg);
+ break;
+ case MEM_GOING_OFFLINE:
+ ret = slab_mem_going_offline_callback(arg);
+ break;
+ case MEM_OFFLINE:
+ case MEM_CANCEL_ONLINE:
+ slab_mem_offline_callback(arg);
+ break;
+ case MEM_ONLINE:
+ case MEM_CANCEL_OFFLINE:
+ break;
+ }
+ if (ret)
+ ret = notifier_from_errno(ret);
+ else
+ ret = NOTIFY_OK;
+ return ret;
+}
+
+static struct notifier_block slab_memory_callback_nb = {
+ .notifier_call = slab_memory_callback,
+ .priority = SLAB_CALLBACK_PRI,
+};
+
+/********************************************************************
+ * Basic setup of slabs
+ *******************************************************************/
+
+/*
+ * Used for early kmem_cache structures that were allocated using
+ * the page allocator. Allocate them properly then fix up the pointers
+ * that may be pointing to the wrong kmem_cache structure.
+ */
+
+static struct kmem_cache * __init bootstrap(struct kmem_cache *static_cache)
+{
+ int node;
+ struct kmem_cache *s = kmem_cache_zalloc(kmem_cache, GFP_NOWAIT);
+ struct kmem_cache_node *n;
+
+ memcpy(s, static_cache, kmem_cache->object_size);
+
+ /*
+ * This runs very early, and only the boot processor is supposed to be
+ * up. Even if it weren't true, IRQs are not up so we couldn't fire
+ * IPIs around.
+ */
+ __flush_cpu_slab(s, smp_processor_id());
+ for_each_kmem_cache_node(s, node, n) {
+ struct slab *p;
+
+ list_for_each_entry(p, &n->partial, slab_list)
+ p->slab_cache = s;
+
+#ifdef CONFIG_SLUB_DEBUG
+ list_for_each_entry(p, &n->full, slab_list)
+ p->slab_cache = s;
+#endif
+ }
+ list_add(&s->list, &slab_caches);
+ return s;
+}
+
+void __init kmem_cache_init(void)
+{
+ static __initdata struct kmem_cache boot_kmem_cache,
+ boot_kmem_cache_node;
+ int node;
+
+ if (debug_guardpage_minorder())
+ slub_max_order = 0;
+
+ /* Print slub debugging pointers without hashing */
+ if (__slub_debug_enabled())
+ no_hash_pointers_enable(NULL);
+
+ kmem_cache_node = &boot_kmem_cache_node;
+ kmem_cache = &boot_kmem_cache;
+
+ /*
+ * Initialize the nodemask for which we will allocate per node
+ * structures. Here we don't need taking slab_mutex yet.
+ */
+ for_each_node_state(node, N_NORMAL_MEMORY)
+ node_set(node, slab_nodes);
+
+ create_boot_cache(kmem_cache_node, "kmem_cache_node",
+ sizeof(struct kmem_cache_node), SLAB_HWCACHE_ALIGN, 0, 0);
+
+ register_hotmemory_notifier(&slab_memory_callback_nb);
+
+ /* Able to allocate the per node structures */
+ slab_state = PARTIAL;
+
+ create_boot_cache(kmem_cache, "kmem_cache",
+ offsetof(struct kmem_cache, node) +
+ nr_node_ids * sizeof(struct kmem_cache_node *),
+ SLAB_HWCACHE_ALIGN, 0, 0);
+
+ kmem_cache = bootstrap(&boot_kmem_cache);
+ kmem_cache_node = bootstrap(&boot_kmem_cache_node);
+
+ /* Now we can use the kmem_cache to allocate kmalloc slabs */
+ setup_kmalloc_cache_index_table();
+ create_kmalloc_caches(0);
+
+ /* Setup random freelists for each cache */
+ init_freelist_randomization();
+
+ cpuhp_setup_state_nocalls(CPUHP_SLUB_DEAD, "slub:dead", NULL,
+ slub_cpu_dead);
+
+ pr_info("SLUB: HWalign=%d, Order=%u-%u, MinObjects=%u, CPUs=%u, Nodes=%u\n",
+ cache_line_size(),
+ slub_min_order, slub_max_order, slub_min_objects,
+ nr_cpu_ids, nr_node_ids);
+}
+
+void __init kmem_cache_init_late(void)
+{
+ flushwq = alloc_workqueue("slub_flushwq", WQ_MEM_RECLAIM, 0);
+ WARN_ON(!flushwq);
+}
+
+struct kmem_cache *
+__kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
+ slab_flags_t flags, void (*ctor)(void *))
+{
+ struct kmem_cache *s;
+
+ s = find_mergeable(size, align, flags, name, ctor);
+ if (s) {
+ if (sysfs_slab_alias(s, name))
+ return NULL;
+
+ s->refcount++;
+
+ /*
+ * Adjust the object sizes so that we clear
+ * the complete object on kzalloc.
+ */
+ s->object_size = max(s->object_size, size);
+ s->inuse = max(s->inuse, ALIGN(size, sizeof(void *)));
+ }
+
+ return s;
+}
+
+int __kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
+{
+ int err;
+
+ err = kmem_cache_open(s, flags);
+ if (err)
+ return err;
+
+ /* Mutex is not taken during early boot */
+ if (slab_state <= UP)
+ return 0;
+
+ err = sysfs_slab_add(s);
+ if (err) {
+ __kmem_cache_release(s);
+ return err;
+ }
+
+ if (s->flags & SLAB_STORE_USER)
+ debugfs_slab_add(s);
+
+ return 0;
+}
+
+#ifdef CONFIG_SYSFS
+static int count_inuse(struct slab *slab)
+{
+ return slab->inuse;
+}
+
+static int count_total(struct slab *slab)
+{
+ return slab->objects;
+}
+#endif
+
+#ifdef CONFIG_SLUB_DEBUG
+static void validate_slab(struct kmem_cache *s, struct slab *slab,
+ unsigned long *obj_map)
+{
+ void *p;
+ void *addr = slab_address(slab);
+
+ if (!check_slab(s, slab) || !on_freelist(s, slab, NULL))
+ return;
+
+ /* Now we know that a valid freelist exists */
+ __fill_map(obj_map, s, slab);
+ for_each_object(p, s, addr, slab->objects) {
+ u8 val = test_bit(__obj_to_index(s, addr, p), obj_map) ?
+ SLUB_RED_INACTIVE : SLUB_RED_ACTIVE;
+
+ if (!check_object(s, slab, p, val))
+ break;
+ }
+}
+
+static int validate_slab_node(struct kmem_cache *s,
+ struct kmem_cache_node *n, unsigned long *obj_map)
+{
+ unsigned long count = 0;
+ struct slab *slab;
+ unsigned long flags;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+
+ list_for_each_entry(slab, &n->partial, slab_list) {
+ validate_slab(s, slab, obj_map);
+ count++;
+ }
+ if (count != n->nr_partial) {
+ pr_err("SLUB %s: %ld partial slabs counted but counter=%ld\n",
+ s->name, count, n->nr_partial);
+ slab_add_kunit_errors();
+ }
+
+ if (!(s->flags & SLAB_STORE_USER))
+ goto out;
+
+ list_for_each_entry(slab, &n->full, slab_list) {
+ validate_slab(s, slab, obj_map);
+ count++;
+ }
+ if (count != atomic_long_read(&n->nr_slabs)) {
+ pr_err("SLUB: %s %ld slabs counted but counter=%ld\n",
+ s->name, count, atomic_long_read(&n->nr_slabs));
+ slab_add_kunit_errors();
+ }
+
+out:
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ return count;
+}
+
+long validate_slab_cache(struct kmem_cache *s)
+{
+ int node;
+ unsigned long count = 0;
+ struct kmem_cache_node *n;
+ unsigned long *obj_map;
+
+ obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
+ if (!obj_map)
+ return -ENOMEM;
+
+ flush_all(s);
+ for_each_kmem_cache_node(s, node, n)
+ count += validate_slab_node(s, n, obj_map);
+
+ bitmap_free(obj_map);
+
+ return count;
+}
+EXPORT_SYMBOL(validate_slab_cache);
+
+#ifdef CONFIG_DEBUG_FS
+/*
+ * Generate lists of code addresses where slabcache objects are allocated
+ * and freed.
+ */
+
+struct location {
+ depot_stack_handle_t handle;
+ unsigned long count;
+ unsigned long addr;
+ unsigned long waste;
+ long long sum_time;
+ long min_time;
+ long max_time;
+ long min_pid;
+ long max_pid;
+ DECLARE_BITMAP(cpus, NR_CPUS);
+ nodemask_t nodes;
+};
+
+struct loc_track {
+ unsigned long max;
+ unsigned long count;
+ struct location *loc;
+ loff_t idx;
+};
+
+static struct dentry *slab_debugfs_root;
+
+static void free_loc_track(struct loc_track *t)
+{
+ if (t->max)
+ free_pages((unsigned long)t->loc,
+ get_order(sizeof(struct location) * t->max));
+}
+
+static int alloc_loc_track(struct loc_track *t, unsigned long max, gfp_t flags)
+{
+ struct location *l;
+ int order;
+
+ order = get_order(sizeof(struct location) * max);
+
+ l = (void *)__get_free_pages(flags, order);
+ if (!l)
+ return 0;
+
+ if (t->count) {
+ memcpy(l, t->loc, sizeof(struct location) * t->count);
+ free_loc_track(t);
+ }
+ t->max = max;
+ t->loc = l;
+ return 1;
+}
+
+static int add_location(struct loc_track *t, struct kmem_cache *s,
+ const struct track *track,
+ unsigned int orig_size)
+{
+ long start, end, pos;
+ struct location *l;
+ unsigned long caddr, chandle, cwaste;
+ unsigned long age = jiffies - track->when;
+ depot_stack_handle_t handle = 0;
+ unsigned int waste = s->object_size - orig_size;
+
+#ifdef CONFIG_STACKDEPOT
+ handle = READ_ONCE(track->handle);
+#endif
+ start = -1;
+ end = t->count;
+
+ for ( ; ; ) {
+ pos = start + (end - start + 1) / 2;
+
+ /*
+ * There is nothing at "end". If we end up there
+ * we need to add something to before end.
+ */
+ if (pos == end)
+ break;
+
+ l = &t->loc[pos];
+ caddr = l->addr;
+ chandle = l->handle;
+ cwaste = l->waste;
+ if ((track->addr == caddr) && (handle == chandle) &&
+ (waste == cwaste)) {
+
+ l->count++;
+ if (track->when) {
+ l->sum_time += age;
+ if (age < l->min_time)
+ l->min_time = age;
+ if (age > l->max_time)
+ l->max_time = age;
+
+ if (track->pid < l->min_pid)
+ l->min_pid = track->pid;
+ if (track->pid > l->max_pid)
+ l->max_pid = track->pid;
+
+ cpumask_set_cpu(track->cpu,
+ to_cpumask(l->cpus));
+ }
+ node_set(page_to_nid(virt_to_page(track)), l->nodes);
+ return 1;
+ }
+
+ if (track->addr < caddr)
+ end = pos;
+ else if (track->addr == caddr && handle < chandle)
+ end = pos;
+ else if (track->addr == caddr && handle == chandle &&
+ waste < cwaste)
+ end = pos;
+ else
+ start = pos;
+ }
+
+ /*
+ * Not found. Insert new tracking element.
+ */
+ if (t->count >= t->max && !alloc_loc_track(t, 2 * t->max, GFP_ATOMIC))
+ return 0;
+
+ l = t->loc + pos;
+ if (pos < t->count)
+ memmove(l + 1, l,
+ (t->count - pos) * sizeof(struct location));
+ t->count++;
+ l->count = 1;
+ l->addr = track->addr;
+ l->sum_time = age;
+ l->min_time = age;
+ l->max_time = age;
+ l->min_pid = track->pid;
+ l->max_pid = track->pid;
+ l->handle = handle;
+ l->waste = waste;
+ cpumask_clear(to_cpumask(l->cpus));
+ cpumask_set_cpu(track->cpu, to_cpumask(l->cpus));
+ nodes_clear(l->nodes);
+ node_set(page_to_nid(virt_to_page(track)), l->nodes);
+ return 1;
+}
+
+static void process_slab(struct loc_track *t, struct kmem_cache *s,
+ struct slab *slab, enum track_item alloc,
+ unsigned long *obj_map)
+{
+ void *addr = slab_address(slab);
+ bool is_alloc = (alloc == TRACK_ALLOC);
+ void *p;
+
+ __fill_map(obj_map, s, slab);
+
+ for_each_object(p, s, addr, slab->objects)
+ if (!test_bit(__obj_to_index(s, addr, p), obj_map))
+ add_location(t, s, get_track(s, p, alloc),
+ is_alloc ? get_orig_size(s, p) :
+ s->object_size);
+}
+#endif /* CONFIG_DEBUG_FS */
+#endif /* CONFIG_SLUB_DEBUG */
+
+#ifdef CONFIG_SYSFS
+enum slab_stat_type {
+ SL_ALL, /* All slabs */
+ SL_PARTIAL, /* Only partially allocated slabs */
+ SL_CPU, /* Only slabs used for cpu caches */
+ SL_OBJECTS, /* Determine allocated objects not slabs */
+ SL_TOTAL /* Determine object capacity not slabs */
+};
+
+#define SO_ALL (1 << SL_ALL)
+#define SO_PARTIAL (1 << SL_PARTIAL)
+#define SO_CPU (1 << SL_CPU)
+#define SO_OBJECTS (1 << SL_OBJECTS)
+#define SO_TOTAL (1 << SL_TOTAL)
+
+static ssize_t show_slab_objects(struct kmem_cache *s,
+ char *buf, unsigned long flags)
+{
+ unsigned long total = 0;
+ int node;
+ int x;
+ unsigned long *nodes;
+ int len = 0;
+
+ nodes = kcalloc(nr_node_ids, sizeof(unsigned long), GFP_KERNEL);
+ if (!nodes)
+ return -ENOMEM;
+
+ if (flags & SO_CPU) {
+ int cpu;
+
+ for_each_possible_cpu(cpu) {
+ struct kmem_cache_cpu *c = per_cpu_ptr(s->cpu_slab,
+ cpu);
+ int node;
+ struct slab *slab;
+
+ slab = READ_ONCE(c->slab);
+ if (!slab)
+ continue;
+
+ node = slab_nid(slab);
+ if (flags & SO_TOTAL)
+ x = slab->objects;
+ else if (flags & SO_OBJECTS)
+ x = slab->inuse;
+ else
+ x = 1;
+
+ total += x;
+ nodes[node] += x;
+
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ slab = slub_percpu_partial_read_once(c);
+ if (slab) {
+ node = slab_nid(slab);
+ if (flags & SO_TOTAL)
+ WARN_ON_ONCE(1);
+ else if (flags & SO_OBJECTS)
+ WARN_ON_ONCE(1);
+ else
+ x = slab->slabs;
+ total += x;
+ nodes[node] += x;
+ }
+#endif
+ }
+ }
+
+ /*
+ * It is impossible to take "mem_hotplug_lock" here with "kernfs_mutex"
+ * already held which will conflict with an existing lock order:
+ *
+ * mem_hotplug_lock->slab_mutex->kernfs_mutex
+ *
+ * We don't really need mem_hotplug_lock (to hold off
+ * slab_mem_going_offline_callback) here because slab's memory hot
+ * unplug code doesn't destroy the kmem_cache->node[] data.
+ */
+
+#ifdef CONFIG_SLUB_DEBUG
+ if (flags & SO_ALL) {
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+
+ if (flags & SO_TOTAL)
+ x = atomic_long_read(&n->total_objects);
+ else if (flags & SO_OBJECTS)
+ x = atomic_long_read(&n->total_objects) -
+ count_partial(n, count_free);
+ else
+ x = atomic_long_read(&n->nr_slabs);
+ total += x;
+ nodes[node] += x;
+ }
+
+ } else
+#endif
+ if (flags & SO_PARTIAL) {
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+ if (flags & SO_TOTAL)
+ x = count_partial(n, count_total);
+ else if (flags & SO_OBJECTS)
+ x = count_partial(n, count_inuse);
+ else
+ x = n->nr_partial;
+ total += x;
+ nodes[node] += x;
+ }
+ }
+
+ len += sysfs_emit_at(buf, len, "%lu", total);
+#ifdef CONFIG_NUMA
+ for (node = 0; node < nr_node_ids; node++) {
+ if (nodes[node])
+ len += sysfs_emit_at(buf, len, " N%d=%lu",
+ node, nodes[node]);
+ }
+#endif
+ len += sysfs_emit_at(buf, len, "\n");
+ kfree(nodes);
+
+ return len;
+}
+
+#define to_slab_attr(n) container_of(n, struct slab_attribute, attr)
+#define to_slab(n) container_of(n, struct kmem_cache, kobj)
+
+struct slab_attribute {
+ struct attribute attr;
+ ssize_t (*show)(struct kmem_cache *s, char *buf);
+ ssize_t (*store)(struct kmem_cache *s, const char *x, size_t count);
+};
+
+#define SLAB_ATTR_RO(_name) \
+ static struct slab_attribute _name##_attr = __ATTR_RO_MODE(_name, 0400)
+
+#define SLAB_ATTR(_name) \
+ static struct slab_attribute _name##_attr = __ATTR_RW_MODE(_name, 0600)
+
+static ssize_t slab_size_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", s->size);
+}
+SLAB_ATTR_RO(slab_size);
+
+static ssize_t align_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", s->align);
+}
+SLAB_ATTR_RO(align);
+
+static ssize_t object_size_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", s->object_size);
+}
+SLAB_ATTR_RO(object_size);
+
+static ssize_t objs_per_slab_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", oo_objects(s->oo));
+}
+SLAB_ATTR_RO(objs_per_slab);
+
+static ssize_t order_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", oo_order(s->oo));
+}
+SLAB_ATTR_RO(order);
+
+static ssize_t min_partial_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%lu\n", s->min_partial);
+}
+
+static ssize_t min_partial_store(struct kmem_cache *s, const char *buf,
+ size_t length)
+{
+ unsigned long min;
+ int err;
+
+ err = kstrtoul(buf, 10, &min);
+ if (err)
+ return err;
+
+ s->min_partial = min;
+ return length;
+}
+SLAB_ATTR(min_partial);
+
+static ssize_t cpu_partial_show(struct kmem_cache *s, char *buf)
+{
+ unsigned int nr_partial = 0;
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ nr_partial = s->cpu_partial;
+#endif
+
+ return sysfs_emit(buf, "%u\n", nr_partial);
+}
+
+static ssize_t cpu_partial_store(struct kmem_cache *s, const char *buf,
+ size_t length)
+{
+ unsigned int objects;
+ int err;
+
+ err = kstrtouint(buf, 10, &objects);
+ if (err)
+ return err;
+ if (objects && !kmem_cache_has_cpu_partial(s))
+ return -EINVAL;
+
+ slub_set_cpu_partial(s, objects);
+ flush_all(s);
+ return length;
+}
+SLAB_ATTR(cpu_partial);
+
+static ssize_t ctor_show(struct kmem_cache *s, char *buf)
+{
+ if (!s->ctor)
+ return 0;
+ return sysfs_emit(buf, "%pS\n", s->ctor);
+}
+SLAB_ATTR_RO(ctor);
+
+static ssize_t aliases_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", s->refcount < 0 ? 0 : s->refcount - 1);
+}
+SLAB_ATTR_RO(aliases);
+
+static ssize_t partial_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_PARTIAL);
+}
+SLAB_ATTR_RO(partial);
+
+static ssize_t cpu_slabs_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_CPU);
+}
+SLAB_ATTR_RO(cpu_slabs);
+
+static ssize_t objects_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_ALL|SO_OBJECTS);
+}
+SLAB_ATTR_RO(objects);
+
+static ssize_t objects_partial_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_PARTIAL|SO_OBJECTS);
+}
+SLAB_ATTR_RO(objects_partial);
+
+static ssize_t slabs_cpu_partial_show(struct kmem_cache *s, char *buf)
+{
+ int objects = 0;
+ int slabs = 0;
+ int cpu __maybe_unused;
+ int len = 0;
+
+#ifdef CONFIG_SLUB_CPU_PARTIAL
+ for_each_online_cpu(cpu) {
+ struct slab *slab;
+
+ slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
+
+ if (slab)
+ slabs += slab->slabs;
+ }
+#endif
+
+ /* Approximate half-full slabs, see slub_set_cpu_partial() */
+ objects = (slabs * oo_objects(s->oo)) / 2;
+ len += sysfs_emit_at(buf, len, "%d(%d)", objects, slabs);
+
+#if defined(CONFIG_SLUB_CPU_PARTIAL) && defined(CONFIG_SMP)
+ for_each_online_cpu(cpu) {
+ struct slab *slab;
+
+ slab = slub_percpu_partial(per_cpu_ptr(s->cpu_slab, cpu));
+ if (slab) {
+ slabs = READ_ONCE(slab->slabs);
+ objects = (slabs * oo_objects(s->oo)) / 2;
+ len += sysfs_emit_at(buf, len, " C%d=%d(%d)",
+ cpu, objects, slabs);
+ }
+ }
+#endif
+ len += sysfs_emit_at(buf, len, "\n");
+
+ return len;
+}
+SLAB_ATTR_RO(slabs_cpu_partial);
+
+static ssize_t reclaim_account_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RECLAIM_ACCOUNT));
+}
+SLAB_ATTR_RO(reclaim_account);
+
+static ssize_t hwcache_align_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_HWCACHE_ALIGN));
+}
+SLAB_ATTR_RO(hwcache_align);
+
+#ifdef CONFIG_ZONE_DMA
+static ssize_t cache_dma_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CACHE_DMA));
+}
+SLAB_ATTR_RO(cache_dma);
+#endif
+
+static ssize_t usersize_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", s->usersize);
+}
+SLAB_ATTR_RO(usersize);
+
+static ssize_t destroy_by_rcu_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TYPESAFE_BY_RCU));
+}
+SLAB_ATTR_RO(destroy_by_rcu);
+
+#ifdef CONFIG_SLUB_DEBUG
+static ssize_t slabs_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_ALL);
+}
+SLAB_ATTR_RO(slabs);
+
+static ssize_t total_objects_show(struct kmem_cache *s, char *buf)
+{
+ return show_slab_objects(s, buf, SO_ALL|SO_TOTAL);
+}
+SLAB_ATTR_RO(total_objects);
+
+static ssize_t sanity_checks_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_CONSISTENCY_CHECKS));
+}
+SLAB_ATTR_RO(sanity_checks);
+
+static ssize_t trace_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_TRACE));
+}
+SLAB_ATTR_RO(trace);
+
+static ssize_t red_zone_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_RED_ZONE));
+}
+
+SLAB_ATTR_RO(red_zone);
+
+static ssize_t poison_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_POISON));
+}
+
+SLAB_ATTR_RO(poison);
+
+static ssize_t store_user_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_STORE_USER));
+}
+
+SLAB_ATTR_RO(store_user);
+
+static ssize_t validate_show(struct kmem_cache *s, char *buf)
+{
+ return 0;
+}
+
+static ssize_t validate_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ int ret = -EINVAL;
+
+ if (buf[0] == '1' && kmem_cache_debug(s)) {
+ ret = validate_slab_cache(s);
+ if (ret >= 0)
+ ret = length;
+ }
+ return ret;
+}
+SLAB_ATTR(validate);
+
+#endif /* CONFIG_SLUB_DEBUG */
+
+#ifdef CONFIG_FAILSLAB
+static ssize_t failslab_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_FAILSLAB));
+}
+SLAB_ATTR_RO(failslab);
+#endif
+
+static ssize_t shrink_show(struct kmem_cache *s, char *buf)
+{
+ return 0;
+}
+
+static ssize_t shrink_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ if (buf[0] == '1')
+ kmem_cache_shrink(s);
+ else
+ return -EINVAL;
+ return length;
+}
+SLAB_ATTR(shrink);
+
+#ifdef CONFIG_NUMA
+static ssize_t remote_node_defrag_ratio_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%u\n", s->remote_node_defrag_ratio / 10);
+}
+
+static ssize_t remote_node_defrag_ratio_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ unsigned int ratio;
+ int err;
+
+ err = kstrtouint(buf, 10, &ratio);
+ if (err)
+ return err;
+ if (ratio > 100)
+ return -ERANGE;
+
+ s->remote_node_defrag_ratio = ratio * 10;
+
+ return length;
+}
+SLAB_ATTR(remote_node_defrag_ratio);
+#endif
+
+#ifdef CONFIG_SLUB_STATS
+static int show_stat(struct kmem_cache *s, char *buf, enum stat_item si)
+{
+ unsigned long sum = 0;
+ int cpu;
+ int len = 0;
+ int *data = kmalloc_array(nr_cpu_ids, sizeof(int), GFP_KERNEL);
+
+ if (!data)
+ return -ENOMEM;
+
+ for_each_online_cpu(cpu) {
+ unsigned x = per_cpu_ptr(s->cpu_slab, cpu)->stat[si];
+
+ data[cpu] = x;
+ sum += x;
+ }
+
+ len += sysfs_emit_at(buf, len, "%lu", sum);
+
+#ifdef CONFIG_SMP
+ for_each_online_cpu(cpu) {
+ if (data[cpu])
+ len += sysfs_emit_at(buf, len, " C%d=%u",
+ cpu, data[cpu]);
+ }
+#endif
+ kfree(data);
+ len += sysfs_emit_at(buf, len, "\n");
+
+ return len;
+}
+
+static void clear_stat(struct kmem_cache *s, enum stat_item si)
+{
+ int cpu;
+
+ for_each_online_cpu(cpu)
+ per_cpu_ptr(s->cpu_slab, cpu)->stat[si] = 0;
+}
+
+#define STAT_ATTR(si, text) \
+static ssize_t text##_show(struct kmem_cache *s, char *buf) \
+{ \
+ return show_stat(s, buf, si); \
+} \
+static ssize_t text##_store(struct kmem_cache *s, \
+ const char *buf, size_t length) \
+{ \
+ if (buf[0] != '0') \
+ return -EINVAL; \
+ clear_stat(s, si); \
+ return length; \
+} \
+SLAB_ATTR(text); \
+
+STAT_ATTR(ALLOC_FASTPATH, alloc_fastpath);
+STAT_ATTR(ALLOC_SLOWPATH, alloc_slowpath);
+STAT_ATTR(FREE_FASTPATH, free_fastpath);
+STAT_ATTR(FREE_SLOWPATH, free_slowpath);
+STAT_ATTR(FREE_FROZEN, free_frozen);
+STAT_ATTR(FREE_ADD_PARTIAL, free_add_partial);
+STAT_ATTR(FREE_REMOVE_PARTIAL, free_remove_partial);
+STAT_ATTR(ALLOC_FROM_PARTIAL, alloc_from_partial);
+STAT_ATTR(ALLOC_SLAB, alloc_slab);
+STAT_ATTR(ALLOC_REFILL, alloc_refill);
+STAT_ATTR(ALLOC_NODE_MISMATCH, alloc_node_mismatch);
+STAT_ATTR(FREE_SLAB, free_slab);
+STAT_ATTR(CPUSLAB_FLUSH, cpuslab_flush);
+STAT_ATTR(DEACTIVATE_FULL, deactivate_full);
+STAT_ATTR(DEACTIVATE_EMPTY, deactivate_empty);
+STAT_ATTR(DEACTIVATE_TO_HEAD, deactivate_to_head);
+STAT_ATTR(DEACTIVATE_TO_TAIL, deactivate_to_tail);
+STAT_ATTR(DEACTIVATE_REMOTE_FREES, deactivate_remote_frees);
+STAT_ATTR(DEACTIVATE_BYPASS, deactivate_bypass);
+STAT_ATTR(ORDER_FALLBACK, order_fallback);
+STAT_ATTR(CMPXCHG_DOUBLE_CPU_FAIL, cmpxchg_double_cpu_fail);
+STAT_ATTR(CMPXCHG_DOUBLE_FAIL, cmpxchg_double_fail);
+STAT_ATTR(CPU_PARTIAL_ALLOC, cpu_partial_alloc);
+STAT_ATTR(CPU_PARTIAL_FREE, cpu_partial_free);
+STAT_ATTR(CPU_PARTIAL_NODE, cpu_partial_node);
+STAT_ATTR(CPU_PARTIAL_DRAIN, cpu_partial_drain);
+#endif /* CONFIG_SLUB_STATS */
+
+#ifdef CONFIG_KFENCE
+static ssize_t skip_kfence_show(struct kmem_cache *s, char *buf)
+{
+ return sysfs_emit(buf, "%d\n", !!(s->flags & SLAB_SKIP_KFENCE));
+}
+
+static ssize_t skip_kfence_store(struct kmem_cache *s,
+ const char *buf, size_t length)
+{
+ int ret = length;
+
+ if (buf[0] == '0')
+ s->flags &= ~SLAB_SKIP_KFENCE;
+ else if (buf[0] == '1')
+ s->flags |= SLAB_SKIP_KFENCE;
+ else
+ ret = -EINVAL;
+
+ return ret;
+}
+SLAB_ATTR(skip_kfence);
+#endif
+
+static struct attribute *slab_attrs[] = {
+ &slab_size_attr.attr,
+ &object_size_attr.attr,
+ &objs_per_slab_attr.attr,
+ &order_attr.attr,
+ &min_partial_attr.attr,
+ &cpu_partial_attr.attr,
+ &objects_attr.attr,
+ &objects_partial_attr.attr,
+ &partial_attr.attr,
+ &cpu_slabs_attr.attr,
+ &ctor_attr.attr,
+ &aliases_attr.attr,
+ &align_attr.attr,
+ &hwcache_align_attr.attr,
+ &reclaim_account_attr.attr,
+ &destroy_by_rcu_attr.attr,
+ &shrink_attr.attr,
+ &slabs_cpu_partial_attr.attr,
+#ifdef CONFIG_SLUB_DEBUG
+ &total_objects_attr.attr,
+ &slabs_attr.attr,
+ &sanity_checks_attr.attr,
+ &trace_attr.attr,
+ &red_zone_attr.attr,
+ &poison_attr.attr,
+ &store_user_attr.attr,
+ &validate_attr.attr,
+#endif
+#ifdef CONFIG_ZONE_DMA
+ &cache_dma_attr.attr,
+#endif
+#ifdef CONFIG_NUMA
+ &remote_node_defrag_ratio_attr.attr,
+#endif
+#ifdef CONFIG_SLUB_STATS
+ &alloc_fastpath_attr.attr,
+ &alloc_slowpath_attr.attr,
+ &free_fastpath_attr.attr,
+ &free_slowpath_attr.attr,
+ &free_frozen_attr.attr,
+ &free_add_partial_attr.attr,
+ &free_remove_partial_attr.attr,
+ &alloc_from_partial_attr.attr,
+ &alloc_slab_attr.attr,
+ &alloc_refill_attr.attr,
+ &alloc_node_mismatch_attr.attr,
+ &free_slab_attr.attr,
+ &cpuslab_flush_attr.attr,
+ &deactivate_full_attr.attr,
+ &deactivate_empty_attr.attr,
+ &deactivate_to_head_attr.attr,
+ &deactivate_to_tail_attr.attr,
+ &deactivate_remote_frees_attr.attr,
+ &deactivate_bypass_attr.attr,
+ &order_fallback_attr.attr,
+ &cmpxchg_double_fail_attr.attr,
+ &cmpxchg_double_cpu_fail_attr.attr,
+ &cpu_partial_alloc_attr.attr,
+ &cpu_partial_free_attr.attr,
+ &cpu_partial_node_attr.attr,
+ &cpu_partial_drain_attr.attr,
+#endif
+#ifdef CONFIG_FAILSLAB
+ &failslab_attr.attr,
+#endif
+ &usersize_attr.attr,
+#ifdef CONFIG_KFENCE
+ &skip_kfence_attr.attr,
+#endif
+
+ NULL
+};
+
+static const struct attribute_group slab_attr_group = {
+ .attrs = slab_attrs,
+};
+
+static ssize_t slab_attr_show(struct kobject *kobj,
+ struct attribute *attr,
+ char *buf)
+{
+ struct slab_attribute *attribute;
+ struct kmem_cache *s;
+
+ attribute = to_slab_attr(attr);
+ s = to_slab(kobj);
+
+ if (!attribute->show)
+ return -EIO;
+
+ return attribute->show(s, buf);
+}
+
+static ssize_t slab_attr_store(struct kobject *kobj,
+ struct attribute *attr,
+ const char *buf, size_t len)
+{
+ struct slab_attribute *attribute;
+ struct kmem_cache *s;
+
+ attribute = to_slab_attr(attr);
+ s = to_slab(kobj);
+
+ if (!attribute->store)
+ return -EIO;
+
+ return attribute->store(s, buf, len);
+}
+
+static void kmem_cache_release(struct kobject *k)
+{
+ slab_kmem_cache_release(to_slab(k));
+}
+
+static const struct sysfs_ops slab_sysfs_ops = {
+ .show = slab_attr_show,
+ .store = slab_attr_store,
+};
+
+static struct kobj_type slab_ktype = {
+ .sysfs_ops = &slab_sysfs_ops,
+ .release = kmem_cache_release,
+};
+
+static struct kset *slab_kset;
+
+static inline struct kset *cache_kset(struct kmem_cache *s)
+{
+ return slab_kset;
+}
+
+#define ID_STR_LENGTH 32
+
+/* Create a unique string id for a slab cache:
+ *
+ * Format :[flags-]size
+ */
+static char *create_unique_id(struct kmem_cache *s)
+{
+ char *name = kmalloc(ID_STR_LENGTH, GFP_KERNEL);
+ char *p = name;
+
+ if (!name)
+ return ERR_PTR(-ENOMEM);
+
+ *p++ = ':';
+ /*
+ * First flags affecting slabcache operations. We will only
+ * get here for aliasable slabs so we do not need to support
+ * too many flags. The flags here must cover all flags that
+ * are matched during merging to guarantee that the id is
+ * unique.
+ */
+ if (s->flags & SLAB_CACHE_DMA)
+ *p++ = 'd';
+ if (s->flags & SLAB_CACHE_DMA32)
+ *p++ = 'D';
+ if (s->flags & SLAB_RECLAIM_ACCOUNT)
+ *p++ = 'a';
+ if (s->flags & SLAB_CONSISTENCY_CHECKS)
+ *p++ = 'F';
+ if (s->flags & SLAB_ACCOUNT)
+ *p++ = 'A';
+ if (p != name + 1)
+ *p++ = '-';
+ p += snprintf(p, ID_STR_LENGTH - (p - name), "%07u", s->size);
+
+ if (WARN_ON(p > name + ID_STR_LENGTH - 1)) {
+ kfree(name);
+ return ERR_PTR(-EINVAL);
+ }
+ kmsan_unpoison_memory(name, p - name);
+ return name;
+}
+
+static int sysfs_slab_add(struct kmem_cache *s)
+{
+ int err;
+ const char *name;
+ struct kset *kset = cache_kset(s);
+ int unmergeable = slab_unmergeable(s);
+
+ if (!kset) {
+ kobject_init(&s->kobj, &slab_ktype);
+ return 0;
+ }
+
+ if (!unmergeable && disable_higher_order_debug &&
+ (slub_debug & DEBUG_METADATA_FLAGS))
+ unmergeable = 1;
+
+ if (unmergeable) {
+ /*
+ * Slabcache can never be merged so we can use the name proper.
+ * This is typically the case for debug situations. In that
+ * case we can catch duplicate names easily.
+ */
+ sysfs_remove_link(&slab_kset->kobj, s->name);
+ name = s->name;
+ } else {
+ /*
+ * Create a unique name for the slab as a target
+ * for the symlinks.
+ */
+ name = create_unique_id(s);
+ if (IS_ERR(name))
+ return PTR_ERR(name);
+ }
+
+ s->kobj.kset = kset;
+ err = kobject_init_and_add(&s->kobj, &slab_ktype, NULL, "%s", name);
+ if (err)
+ goto out;
+
+ err = sysfs_create_group(&s->kobj, &slab_attr_group);
+ if (err)
+ goto out_del_kobj;
+
+ if (!unmergeable) {
+ /* Setup first alias */
+ sysfs_slab_alias(s, s->name);
+ }
+out:
+ if (!unmergeable)
+ kfree(name);
+ return err;
+out_del_kobj:
+ kobject_del(&s->kobj);
+ goto out;
+}
+
+void sysfs_slab_unlink(struct kmem_cache *s)
+{
+ if (slab_state >= FULL)
+ kobject_del(&s->kobj);
+}
+
+void sysfs_slab_release(struct kmem_cache *s)
+{
+ if (slab_state >= FULL)
+ kobject_put(&s->kobj);
+}
+
+/*
+ * Need to buffer aliases during bootup until sysfs becomes
+ * available lest we lose that information.
+ */
+struct saved_alias {
+ struct kmem_cache *s;
+ const char *name;
+ struct saved_alias *next;
+};
+
+static struct saved_alias *alias_list;
+
+static int sysfs_slab_alias(struct kmem_cache *s, const char *name)
+{
+ struct saved_alias *al;
+
+ if (slab_state == FULL) {
+ /*
+ * If we have a leftover link then remove it.
+ */
+ sysfs_remove_link(&slab_kset->kobj, name);
+ return sysfs_create_link(&slab_kset->kobj, &s->kobj, name);
+ }
+
+ al = kmalloc(sizeof(struct saved_alias), GFP_KERNEL);
+ if (!al)
+ return -ENOMEM;
+
+ al->s = s;
+ al->name = name;
+ al->next = alias_list;
+ alias_list = al;
+ kmsan_unpoison_memory(al, sizeof(*al));
+ return 0;
+}
+
+static int __init slab_sysfs_init(void)
+{
+ struct kmem_cache *s;
+ int err;
+
+ mutex_lock(&slab_mutex);
+
+ slab_kset = kset_create_and_add("slab", NULL, kernel_kobj);
+ if (!slab_kset) {
+ mutex_unlock(&slab_mutex);
+ pr_err("Cannot register slab subsystem.\n");
+ return -ENOSYS;
+ }
+
+ slab_state = FULL;
+
+ list_for_each_entry(s, &slab_caches, list) {
+ err = sysfs_slab_add(s);
+ if (err)
+ pr_err("SLUB: Unable to add boot slab %s to sysfs\n",
+ s->name);
+ }
+
+ while (alias_list) {
+ struct saved_alias *al = alias_list;
+
+ alias_list = alias_list->next;
+ err = sysfs_slab_alias(al->s, al->name);
+ if (err)
+ pr_err("SLUB: Unable to add boot slab alias %s to sysfs\n",
+ al->name);
+ kfree(al);
+ }
+
+ mutex_unlock(&slab_mutex);
+ return 0;
+}
+
+__initcall(slab_sysfs_init);
+#endif /* CONFIG_SYSFS */
+
+#if defined(CONFIG_SLUB_DEBUG) && defined(CONFIG_DEBUG_FS)
+static int slab_debugfs_show(struct seq_file *seq, void *v)
+{
+ struct loc_track *t = seq->private;
+ struct location *l;
+ unsigned long idx;
+
+ idx = (unsigned long) t->idx;
+ if (idx < t->count) {
+ l = &t->loc[idx];
+
+ seq_printf(seq, "%7ld ", l->count);
+
+ if (l->addr)
+ seq_printf(seq, "%pS", (void *)l->addr);
+ else
+ seq_puts(seq, "<not-available>");
+
+ if (l->waste)
+ seq_printf(seq, " waste=%lu/%lu",
+ l->count * l->waste, l->waste);
+
+ if (l->sum_time != l->min_time) {
+ seq_printf(seq, " age=%ld/%llu/%ld",
+ l->min_time, div_u64(l->sum_time, l->count),
+ l->max_time);
+ } else
+ seq_printf(seq, " age=%ld", l->min_time);
+
+ if (l->min_pid != l->max_pid)
+ seq_printf(seq, " pid=%ld-%ld", l->min_pid, l->max_pid);
+ else
+ seq_printf(seq, " pid=%ld",
+ l->min_pid);
+
+ if (num_online_cpus() > 1 && !cpumask_empty(to_cpumask(l->cpus)))
+ seq_printf(seq, " cpus=%*pbl",
+ cpumask_pr_args(to_cpumask(l->cpus)));
+
+ if (nr_online_nodes > 1 && !nodes_empty(l->nodes))
+ seq_printf(seq, " nodes=%*pbl",
+ nodemask_pr_args(&l->nodes));
+
+#ifdef CONFIG_STACKDEPOT
+ {
+ depot_stack_handle_t handle;
+ unsigned long *entries;
+ unsigned int nr_entries, j;
+
+ handle = READ_ONCE(l->handle);
+ if (handle) {
+ nr_entries = stack_depot_fetch(handle, &entries);
+ seq_puts(seq, "\n");
+ for (j = 0; j < nr_entries; j++)
+ seq_printf(seq, " %pS\n", (void *)entries[j]);
+ }
+ }
+#endif
+ seq_puts(seq, "\n");
+ }
+
+ if (!idx && !t->count)
+ seq_puts(seq, "No data\n");
+
+ return 0;
+}
+
+static void slab_debugfs_stop(struct seq_file *seq, void *v)
+{
+}
+
+static void *slab_debugfs_next(struct seq_file *seq, void *v, loff_t *ppos)
+{
+ struct loc_track *t = seq->private;
+
+ t->idx = ++(*ppos);
+ if (*ppos <= t->count)
+ return ppos;
+
+ return NULL;
+}
+
+static int cmp_loc_by_count(const void *a, const void *b, const void *data)
+{
+ struct location *loc1 = (struct location *)a;
+ struct location *loc2 = (struct location *)b;
+
+ if (loc1->count > loc2->count)
+ return -1;
+ else
+ return 1;
+}
+
+static void *slab_debugfs_start(struct seq_file *seq, loff_t *ppos)
+{
+ struct loc_track *t = seq->private;
+
+ t->idx = *ppos;
+ return ppos;
+}
+
+static const struct seq_operations slab_debugfs_sops = {
+ .start = slab_debugfs_start,
+ .next = slab_debugfs_next,
+ .stop = slab_debugfs_stop,
+ .show = slab_debugfs_show,
+};
+
+static int slab_debug_trace_open(struct inode *inode, struct file *filep)
+{
+
+ struct kmem_cache_node *n;
+ enum track_item alloc;
+ int node;
+ struct loc_track *t = __seq_open_private(filep, &slab_debugfs_sops,
+ sizeof(struct loc_track));
+ struct kmem_cache *s = file_inode(filep)->i_private;
+ unsigned long *obj_map;
+
+ if (!t)
+ return -ENOMEM;
+
+ obj_map = bitmap_alloc(oo_objects(s->oo), GFP_KERNEL);
+ if (!obj_map) {
+ seq_release_private(inode, filep);
+ return -ENOMEM;
+ }
+
+ if (strcmp(filep->f_path.dentry->d_name.name, "alloc_traces") == 0)
+ alloc = TRACK_ALLOC;
+ else
+ alloc = TRACK_FREE;
+
+ if (!alloc_loc_track(t, PAGE_SIZE / sizeof(struct location), GFP_KERNEL)) {
+ bitmap_free(obj_map);
+ seq_release_private(inode, filep);
+ return -ENOMEM;
+ }
+
+ for_each_kmem_cache_node(s, node, n) {
+ unsigned long flags;
+ struct slab *slab;
+
+ if (!atomic_long_read(&n->nr_slabs))
+ continue;
+
+ spin_lock_irqsave(&n->list_lock, flags);
+ list_for_each_entry(slab, &n->partial, slab_list)
+ process_slab(t, s, slab, alloc, obj_map);
+ list_for_each_entry(slab, &n->full, slab_list)
+ process_slab(t, s, slab, alloc, obj_map);
+ spin_unlock_irqrestore(&n->list_lock, flags);
+ }
+
+ /* Sort locations by count */
+ sort_r(t->loc, t->count, sizeof(struct location),
+ cmp_loc_by_count, NULL, NULL);
+
+ bitmap_free(obj_map);
+ return 0;
+}
+
+static int slab_debug_trace_release(struct inode *inode, struct file *file)
+{
+ struct seq_file *seq = file->private_data;
+ struct loc_track *t = seq->private;
+
+ free_loc_track(t);
+ return seq_release_private(inode, file);
+}
+
+static const struct file_operations slab_debugfs_fops = {
+ .open = slab_debug_trace_open,
+ .read = seq_read,
+ .llseek = seq_lseek,
+ .release = slab_debug_trace_release,
+};
+
+static void debugfs_slab_add(struct kmem_cache *s)
+{
+ struct dentry *slab_cache_dir;
+
+ if (unlikely(!slab_debugfs_root))
+ return;
+
+ slab_cache_dir = debugfs_create_dir(s->name, slab_debugfs_root);
+
+ debugfs_create_file("alloc_traces", 0400,
+ slab_cache_dir, s, &slab_debugfs_fops);
+
+ debugfs_create_file("free_traces", 0400,
+ slab_cache_dir, s, &slab_debugfs_fops);
+}
+
+void debugfs_slab_release(struct kmem_cache *s)
+{
+ debugfs_remove_recursive(debugfs_lookup(s->name, slab_debugfs_root));
+}
+
+static int __init slab_debugfs_init(void)
+{
+ struct kmem_cache *s;
+
+ slab_debugfs_root = debugfs_create_dir("slab", NULL);
+
+ list_for_each_entry(s, &slab_caches, list)
+ if (s->flags & SLAB_STORE_USER)
+ debugfs_slab_add(s);
+
+ return 0;
+
+}
+__initcall(slab_debugfs_init);
+#endif
+/*
+ * The /proc/slabinfo ABI
+ */
+#ifdef CONFIG_SLUB_DEBUG
+void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo)
+{
+ unsigned long nr_slabs = 0;
+ unsigned long nr_objs = 0;
+ unsigned long nr_free = 0;
+ int node;
+ struct kmem_cache_node *n;
+
+ for_each_kmem_cache_node(s, node, n) {
+ nr_slabs += node_nr_slabs(n);
+ nr_objs += node_nr_objs(n);
+ nr_free += count_partial(n, count_free);
+ }
+
+ sinfo->active_objs = nr_objs - nr_free;
+ sinfo->num_objs = nr_objs;
+ sinfo->active_slabs = nr_slabs;
+ sinfo->num_slabs = nr_slabs;
+ sinfo->objects_per_slab = oo_objects(s->oo);
+ sinfo->cache_order = oo_order(s->oo);
+}
+
+void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s)
+{
+}
+
+ssize_t slabinfo_write(struct file *file, const char __user *buffer,
+ size_t count, loff_t *ppos)
+{
+ return -EIO;
+}
+#endif /* CONFIG_SLUB_DEBUG */