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-rw-r--r--mm/debug.c324
1 files changed, 324 insertions, 0 deletions
diff --git a/mm/debug.c b/mm/debug.c
new file mode 100644
index 000000000..ccca576b2
--- /dev/null
+++ b/mm/debug.c
@@ -0,0 +1,324 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * mm/debug.c
+ *
+ * mm/ specific debug routines.
+ *
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/trace_events.h>
+#include <linux/memcontrol.h>
+#include <trace/events/mmflags.h>
+#include <linux/migrate.h>
+#include <linux/page_owner.h>
+#include <linux/ctype.h>
+
+#include "internal.h"
+
+const char *migrate_reason_names[MR_TYPES] = {
+ "compaction",
+ "memory_failure",
+ "memory_hotplug",
+ "syscall_or_cpuset",
+ "mempolicy_mbind",
+ "numa_misplaced",
+ "cma",
+};
+
+const struct trace_print_flags pageflag_names[] = {
+ __def_pageflag_names,
+ {0, NULL}
+};
+
+const struct trace_print_flags gfpflag_names[] = {
+ __def_gfpflag_names,
+ {0, NULL}
+};
+
+const struct trace_print_flags vmaflag_names[] = {
+ __def_vmaflag_names,
+ {0, NULL}
+};
+
+void __dump_page(struct page *page, const char *reason)
+{
+ struct page *head = compound_head(page);
+ struct address_space *mapping;
+ bool page_poisoned = PagePoisoned(page);
+ bool compound = PageCompound(page);
+ /*
+ * Accessing the pageblock without the zone lock. It could change to
+ * "isolate" again in the meantime, but since we are just dumping the
+ * state for debugging, it should be fine to accept a bit of
+ * inaccuracy here due to racing.
+ */
+ bool page_cma = is_migrate_cma_page(page);
+ int mapcount;
+ char *type = "";
+
+ /*
+ * If struct page is poisoned don't access Page*() functions as that
+ * leads to recursive loop. Page*() check for poisoned pages, and calls
+ * dump_page() when detected.
+ */
+ if (page_poisoned) {
+ pr_warn("page:%px is uninitialized and poisoned", page);
+ goto hex_only;
+ }
+
+ if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
+ /*
+ * Corrupt page, so we cannot call page_mapping. Instead, do a
+ * safe subset of the steps that page_mapping() does. Caution:
+ * this will be misleading for tail pages, PageSwapCache pages,
+ * and potentially other situations. (See the page_mapping()
+ * implementation for what's missing here.)
+ */
+ unsigned long tmp = (unsigned long)page->mapping;
+
+ if (tmp & PAGE_MAPPING_ANON)
+ mapping = NULL;
+ else
+ mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
+ head = page;
+ compound = false;
+ } else {
+ mapping = page_mapping(page);
+ }
+
+ /*
+ * Avoid VM_BUG_ON() in page_mapcount().
+ * page->_mapcount space in struct page is used by sl[aou]b pages to
+ * encode own info.
+ */
+ mapcount = PageSlab(head) ? 0 : page_mapcount(page);
+
+ pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
+ page, page_ref_count(head), mapcount, mapping,
+ page_to_pgoff(page), page_to_pfn(page));
+ if (compound) {
+ if (hpage_pincount_available(page)) {
+ pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
+ head, compound_order(head),
+ head_compound_mapcount(head),
+ head_compound_pincount(head));
+ } else {
+ pr_warn("head:%p order:%u compound_mapcount:%d\n",
+ head, compound_order(head),
+ head_compound_mapcount(head));
+ }
+ }
+ if (PageKsm(page))
+ type = "ksm ";
+ else if (PageAnon(page))
+ type = "anon ";
+ else if (mapping) {
+ struct inode *host;
+ const struct address_space_operations *a_ops;
+ struct hlist_node *dentry_first;
+ struct dentry *dentry_ptr;
+ struct dentry dentry;
+ unsigned long ino;
+
+ /*
+ * mapping can be invalid pointer and we don't want to crash
+ * accessing it, so probe everything depending on it carefully
+ */
+ if (get_kernel_nofault(host, &mapping->host) ||
+ get_kernel_nofault(a_ops, &mapping->a_ops)) {
+ pr_warn("failed to read mapping contents, not a valid kernel address?\n");
+ goto out_mapping;
+ }
+
+ if (!host) {
+ pr_warn("aops:%ps\n", a_ops);
+ goto out_mapping;
+ }
+
+ if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
+ get_kernel_nofault(ino, &host->i_ino)) {
+ pr_warn("aops:%ps with invalid host inode %px\n",
+ a_ops, host);
+ goto out_mapping;
+ }
+
+ if (!dentry_first) {
+ pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
+ goto out_mapping;
+ }
+
+ dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
+ if (get_kernel_nofault(dentry, dentry_ptr)) {
+ pr_warn("aops:%ps ino:%lx with invalid dentry %px\n",
+ a_ops, ino, dentry_ptr);
+ } else {
+ /*
+ * if dentry is corrupted, the %pd handler may still
+ * crash, but it's unlikely that we reach here with a
+ * corrupted struct page
+ */
+ pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
+ a_ops, ino, &dentry);
+ }
+ }
+out_mapping:
+ BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
+
+ pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
+ page_cma ? " CMA" : "");
+
+hex_only:
+ print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
+ sizeof(unsigned long), page,
+ sizeof(struct page), false);
+ if (head != page)
+ print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
+ sizeof(unsigned long), head,
+ sizeof(struct page), false);
+
+ if (reason)
+ pr_warn("page dumped because: %s\n", reason);
+
+#ifdef CONFIG_MEMCG
+ if (!page_poisoned && page->mem_cgroup)
+ pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
+#endif
+}
+
+void dump_page(struct page *page, const char *reason)
+{
+ __dump_page(page, reason);
+ dump_page_owner(page);
+}
+EXPORT_SYMBOL(dump_page);
+
+#ifdef CONFIG_DEBUG_VM
+
+void dump_vma(const struct vm_area_struct *vma)
+{
+ pr_emerg("vma %px start %px end %px\n"
+ "next %px prev %px mm %px\n"
+ "prot %lx anon_vma %px vm_ops %px\n"
+ "pgoff %lx file %px private_data %px\n"
+ "flags: %#lx(%pGv)\n",
+ vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
+ vma->vm_prev, vma->vm_mm,
+ (unsigned long)pgprot_val(vma->vm_page_prot),
+ vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
+ vma->vm_file, vma->vm_private_data,
+ vma->vm_flags, &vma->vm_flags);
+}
+EXPORT_SYMBOL(dump_vma);
+
+void dump_mm(const struct mm_struct *mm)
+{
+ pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
+#ifdef CONFIG_MMU
+ "get_unmapped_area %px\n"
+#endif
+ "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
+ "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
+ "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
+ "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
+ "start_code %lx end_code %lx start_data %lx end_data %lx\n"
+ "start_brk %lx brk %lx start_stack %lx\n"
+ "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
+ "binfmt %px flags %lx core_state %px\n"
+#ifdef CONFIG_AIO
+ "ioctx_table %px\n"
+#endif
+#ifdef CONFIG_MEMCG
+ "owner %px "
+#endif
+ "exe_file %px\n"
+#ifdef CONFIG_MMU_NOTIFIER
+ "notifier_subscriptions %px\n"
+#endif
+#ifdef CONFIG_NUMA_BALANCING
+ "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
+#endif
+ "tlb_flush_pending %d\n"
+ "def_flags: %#lx(%pGv)\n",
+
+ mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
+#ifdef CONFIG_MMU
+ mm->get_unmapped_area,
+#endif
+ mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
+ mm->pgd, atomic_read(&mm->mm_users),
+ atomic_read(&mm->mm_count),
+ mm_pgtables_bytes(mm),
+ mm->map_count,
+ mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
+ (u64)atomic64_read(&mm->pinned_vm),
+ mm->data_vm, mm->exec_vm, mm->stack_vm,
+ mm->start_code, mm->end_code, mm->start_data, mm->end_data,
+ mm->start_brk, mm->brk, mm->start_stack,
+ mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
+ mm->binfmt, mm->flags, mm->core_state,
+#ifdef CONFIG_AIO
+ mm->ioctx_table,
+#endif
+#ifdef CONFIG_MEMCG
+ mm->owner,
+#endif
+ mm->exe_file,
+#ifdef CONFIG_MMU_NOTIFIER
+ mm->notifier_subscriptions,
+#endif
+#ifdef CONFIG_NUMA_BALANCING
+ mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
+#endif
+ atomic_read(&mm->tlb_flush_pending),
+ mm->def_flags, &mm->def_flags
+ );
+}
+
+static bool page_init_poisoning __read_mostly = true;
+
+static int __init setup_vm_debug(char *str)
+{
+ bool __page_init_poisoning = true;
+
+ /*
+ * Calling vm_debug with no arguments is equivalent to requesting
+ * to enable all debugging options we can control.
+ */
+ if (*str++ != '=' || !*str)
+ goto out;
+
+ __page_init_poisoning = false;
+ if (*str == '-')
+ goto out;
+
+ while (*str) {
+ switch (tolower(*str)) {
+ case'p':
+ __page_init_poisoning = true;
+ break;
+ default:
+ pr_err("vm_debug option '%c' unknown. skipped\n",
+ *str);
+ }
+
+ str++;
+ }
+out:
+ if (page_init_poisoning && !__page_init_poisoning)
+ pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
+
+ page_init_poisoning = __page_init_poisoning;
+
+ return 1;
+}
+__setup("vm_debug", setup_vm_debug);
+
+void page_init_poison(struct page *page, size_t size)
+{
+ if (page_init_poisoning)
+ memset(page, PAGE_POISON_PATTERN, size);
+}
+EXPORT_SYMBOL_GPL(page_init_poison);
+#endif /* CONFIG_DEBUG_VM */