1 files changed, 364 insertions, 0 deletions
diff --git a/mm/debug.c b/mm/debug.c
new file mode 100644
index 000000000000..77fa8fe1d641
--- /dev/null
+++ b/mm/debug.c
@@ -0,0 +1,364 @@
+// 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}
+};
+
+#define DEF_PAGETYPE_NAME(_name) [PGTY_##_name - 0xf0] =  __stringify(_name)
+
+static const char *page_type_names[] = {
+	DEF_PAGETYPE_NAME(slab),
+	DEF_PAGETYPE_NAME(hugetlb),
+	DEF_PAGETYPE_NAME(offline),
+	DEF_PAGETYPE_NAME(guard),
+	DEF_PAGETYPE_NAME(table),
+	DEF_PAGETYPE_NAME(buddy),
+	DEF_PAGETYPE_NAME(unaccepted),
+};
+
+static const char *page_type_name(unsigned int page_type)
+{
+	unsigned i = (page_type >> 24) - 0xf0;
+
+	if (i >= ARRAY_SIZE(page_type_names))
+		return "unknown";
+	return page_type_names[i];
+}
+
+static void __dump_folio(const struct folio *folio, const struct page *page,
+		unsigned long pfn, unsigned long idx)
+{
+	struct address_space *mapping = folio_mapping(folio);
+	int mapcount = atomic_read(&page->_mapcount) + 1;
+	char *type = "";
+
+	if (page_mapcount_is_type(mapcount))
+		mapcount = 0;
+
+	pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
+			folio_ref_count(folio), mapcount, mapping,
+			folio->index + idx, pfn);
+	if (folio_test_large(folio)) {
+		int pincount = 0;
+
+		if (folio_has_pincount(folio))
+			pincount = atomic_read(&folio->_pincount);
+
+		pr_warn("head: order:%u mapcount:%d entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
+				folio_order(folio),
+				folio_mapcount(folio),
+				folio_entire_mapcount(folio),
+				folio_nr_pages_mapped(folio),
+				pincount);
+	}
+
+#ifdef CONFIG_MEMCG
+	if (folio->memcg_data)
+		pr_warn("memcg:%lx\n", folio->memcg_data);
+#endif
+	if (folio_test_ksm(folio))
+		type = "ksm ";
+	else if (folio_test_anon(folio))
+		type = "anon ";
+	else if (mapping)
+		dump_mapping(mapping);
+	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
+
+	/*
+	 * 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.
+	 */
+	pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
+		is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
+	if (page_has_type(&folio->page))
+		pr_warn("page_type: %x(%s)\n", folio->page.page_type >> 24,
+				page_type_name(folio->page.page_type));
+
+	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
+			sizeof(unsigned long), page,
+			sizeof(struct page), false);
+	if (folio_test_large(folio))
+		print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
+			sizeof(unsigned long), folio,
+			2 * sizeof(struct page), false);
+}
+
+static void __dump_page(const struct page *page)
+{
+	struct page_snapshot ps;
+
+	snapshot_page(&ps, page);
+	if (!snapshot_page_is_faithful(&ps))
+		pr_warn("page does not match folio\n");
+
+	__dump_folio(&ps.folio_snapshot, &ps.page_snapshot, ps.pfn, ps.idx);
+}
+
+void dump_page(const struct page *page, const char *reason)
+{
+	if (PagePoisoned(page))
+		pr_warn("page:%p is uninitialized and poisoned\n", 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"
+#ifdef CONFIG_PER_VMA_LOCK
+		"refcnt %x\n"
+#endif
+		"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,
+#ifdef CONFIG_PER_VMA_LOCK
+		refcount_read(&vma->vm_refcnt),
+#endif
+		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"
+		"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 %*pb\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,
+		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, NUM_MM_FLAG_BITS, __mm_flags_get_bitmap(mm),
+#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
+	);
+}
+EXPORT_SYMBOL(dump_mm);
+
+void dump_vmg(const struct vma_merge_struct *vmg, const char *reason)
+{
+	if (reason)
+		pr_warn("vmg %px dumped because: %s\n", vmg, reason);
+
+	if (!vmg) {
+		pr_warn("vmg %px state: (NULL)\n", vmg);
+		return;
+	}
+
+	pr_warn("vmg %px state: mm %px pgoff %lx\n"
+		"vmi %px [%lx,%lx)\n"
+		"prev %px middle %px next %px target %px\n"
+		"start %lx end %lx flags %lx\n"
+		"file %px anon_vma %px policy %px\n"
+		"uffd_ctx %px\n"
+		"anon_name %px\n"
+		"state %x\n"
+		"just_expand %d\n"
+		"__adjust_middle_start %d __adjust_next_start %d\n"
+		"__remove_middle %d __remove_next %d\n",
+		vmg, vmg->mm, vmg->pgoff,
+		vmg->vmi, vmg->vmi ? vma_iter_addr(vmg->vmi) : 0,
+		vmg->vmi ? vma_iter_end(vmg->vmi) : 0,
+		vmg->prev, vmg->middle, vmg->next, vmg->target,
+		vmg->start, vmg->end, vmg->vm_flags,
+		vmg->file, vmg->anon_vma, vmg->policy,
+#ifdef CONFIG_USERFAULTFD
+		vmg->uffd_ctx.ctx,
+#else
+		(void *)0,
+#endif
+		vmg->anon_name,
+		(int)vmg->state,
+		vmg->just_expand,
+		vmg->__adjust_middle_start, vmg->__adjust_next_start,
+		vmg->__remove_middle, vmg->__remove_next);
+
+	if (vmg->mm) {
+		pr_warn("vmg %px mm:\n", vmg);
+		dump_mm(vmg->mm);
+	} else {
+		pr_warn("vmg %px mm: (NULL)\n", vmg);
+	}
+
+	if (vmg->prev) {
+		pr_warn("vmg %px prev:\n", vmg);
+		dump_vma(vmg->prev);
+	} else {
+		pr_warn("vmg %px prev: (NULL)\n", vmg);
+	}
+
+	if (vmg->middle) {
+		pr_warn("vmg %px middle:\n", vmg);
+		dump_vma(vmg->middle);
+	} else {
+		pr_warn("vmg %px middle: (NULL)\n", vmg);
+	}
+
+	if (vmg->next) {
+		pr_warn("vmg %px next:\n", vmg);
+		dump_vma(vmg->next);
+	} else {
+		pr_warn("vmg %px next: (NULL)\n", vmg);
+	}
+
+#ifdef CONFIG_DEBUG_VM_MAPLE_TREE
+	if (vmg->vmi) {
+		pr_warn("vmg %px vmi:\n", vmg);
+		vma_iter_dump_tree(vmg->vmi);
+	} else {
+		pr_warn("vmg %px vmi: (NULL)\n", vmg);
+	}
+#endif
+}
+EXPORT_SYMBOL(dump_vmg);
+
+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);
+}
+
+void vma_iter_dump_tree(const struct vma_iterator *vmi)
+{
+#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
+	mas_dump(&vmi->mas);
+	mt_dump(vmi->mas.tree, mt_dump_hex);
+#endif	/* CONFIG_DEBUG_VM_MAPLE_TREE */
+}
+
+#endif		/* CONFIG_DEBUG_VM */