1 files changed, 262 insertions, 0 deletions
diff --git a/mm/debug.c b/mm/debug.c
new file mode 100644
index 000000000..0fd15ba70
--- /dev/null
+++ b/mm/debug.c
@@ -0,0 +1,262 @@
+// 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"
+#include <trace/events/migrate.h>
+
+/*
+ * Define EM() and EMe() so that MIGRATE_REASON from trace/events/migrate.h can
+ * be used to populate migrate_reason_names[].
+ */
+#undef EM
+#undef EMe
+#define EM(a, b)	b,
+#define EMe(a, b)	b
+
+const char *migrate_reason_names[MR_TYPES] = {
+	MIGRATE_REASON
+};
+
+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}
+};
+
+static void __dump_page(struct page *page)
+{
+	struct folio *folio = page_folio(page);
+	struct page *head = &folio->page;
+	struct address_space *mapping;
+	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 (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;
+		folio = (struct folio *)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) {
+		pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
+				head, compound_order(head),
+				folio_entire_mapcount(folio),
+				head_compound_pincount(head));
+	}
+
+#ifdef CONFIG_MEMCG
+	if (head->memcg_data)
+		pr_warn("memcg:%lx\n", head->memcg_data);
+#endif
+	if (PageKsm(page))
+		type = "ksm ";
+	else if (PageAnon(page))
+		type = "anon ";
+	else if (mapping)
+		dump_mapping(mapping);
+	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
+
+	pr_warn("%sflags: %pGp%s\n", type, &head->flags,
+		page_cma ? " CMA" : "");
+	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);
+}
+
+void dump_page(struct page *page, const char *reason)
+{
+	if (PagePoisoned(page))
+		pr_warn("page:%p is uninitialized and poisoned", page);
+	else
+		__dump_page(page);
+	if (reason)
+		pr_warn("page dumped because: %s\n", 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 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_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 task_size %lu\n"
+#ifdef CONFIG_MMU
+		"get_unmapped_area %px\n"
+#endif
+		"mmap_base %lu mmap_legacy_base %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\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->task_size,
+#ifdef CONFIG_MMU
+		mm->get_unmapped_area,
+#endif
+		mm->mmap_base, mm->mmap_legacy_base,
+		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,
+#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);
+}
+#endif		/* CONFIG_DEBUG_VM */