1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * mm/debug.c
  4 *
  5 * mm/ specific debug routines.
  6 *
  7 */
  8
  9#include <linux/kernel.h>
 10#include <linux/mm.h>
 11#include <linux/trace_events.h>
 12#include <linux/memcontrol.h>
 13#include <trace/events/mmflags.h>
 14#include <linux/migrate.h>
 15#include <linux/page_owner.h>
 16#include <linux/ctype.h>
 17
 18#include "internal.h"
 19#include <trace/events/migrate.h>
 20
 21/*
 22 * Define EM() and EMe() so that MIGRATE_REASON from trace/events/migrate.h can
 23 * be used to populate migrate_reason_names[].
 24 */
 25#undef EM
 26#undef EMe
 27#define EM(a, b)	b,
 28#define EMe(a, b)	b
 29
 30const char *migrate_reason_names[MR_TYPES] = {
 31	MIGRATE_REASON
 32};
 33
 34const struct trace_print_flags pageflag_names[] = {
 35	__def_pageflag_names,
 36	{0, NULL}
 37};
 38
 39const struct trace_print_flags gfpflag_names[] = {
 40	__def_gfpflag_names,
 41	{0, NULL}
 42};
 43
 44const struct trace_print_flags vmaflag_names[] = {
 45	__def_vmaflag_names,
 46	{0, NULL}
 47};
 48
 49static void __dump_page(struct page *page)
 50{
 51	struct folio *folio = page_folio(page);
 52	struct page *head = &folio->page;
 53	struct address_space *mapping;
 54	bool compound = PageCompound(page);
 55	/*
 56	 * Accessing the pageblock without the zone lock. It could change to
 57	 * "isolate" again in the meantime, but since we are just dumping the
 58	 * state for debugging, it should be fine to accept a bit of
 59	 * inaccuracy here due to racing.
 60	 */
 61	bool page_cma = is_migrate_cma_page(page);
 62	int mapcount;
 63	char *type = "";
 64
 65	if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
 66		/*
 67		 * Corrupt page, so we cannot call page_mapping. Instead, do a
 68		 * safe subset of the steps that page_mapping() does. Caution:
 69		 * this will be misleading for tail pages, PageSwapCache pages,
 70		 * and potentially other situations. (See the page_mapping()
 71		 * implementation for what's missing here.)
 72		 */
 73		unsigned long tmp = (unsigned long)page->mapping;
 74
 75		if (tmp & PAGE_MAPPING_ANON)
 76			mapping = NULL;
 77		else
 78			mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
 79		head = page;
 80		folio = (struct folio *)page;
 81		compound = false;
 82	} else {
 83		mapping = page_mapping(page);
 84	}
 85
 86	/*
 87	 * Avoid VM_BUG_ON() in page_mapcount().
 88	 * page->_mapcount space in struct page is used by sl[aou]b pages to
 89	 * encode own info.
 90	 */
 91	mapcount = PageSlab(head) ? 0 : page_mapcount(page);
 92
 93	pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
 94			page, page_ref_count(head), mapcount, mapping,
 95			page_to_pgoff(page), page_to_pfn(page));
 96	if (compound) {
 97		pr_warn("head:%p order:%u compound_mapcount:%d subpages_mapcount:%d compound_pincount:%d\n",
 98				head, compound_order(head),
 99				head_compound_mapcount(head),
100				head_subpages_mapcount(head),
101				head_compound_pincount(head));
102	}
103
104#ifdef CONFIG_MEMCG
105	if (head->memcg_data)
106		pr_warn("memcg:%lx\n", head->memcg_data);
107#endif
108	if (PageKsm(page))
109		type = "ksm ";
110	else if (PageAnon(page))
111		type = "anon ";
112	else if (mapping)
113		dump_mapping(mapping);
114	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
115
116	pr_warn("%sflags: %pGp%s\n", type, &head->flags,
117		page_cma ? " CMA" : "");
118	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
119			sizeof(unsigned long), page,
120			sizeof(struct page), false);
121	if (head != page)
122		print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
123			sizeof(unsigned long), head,
124			sizeof(struct page), false);
125}
126
127void dump_page(struct page *page, const char *reason)
128{
129	if (PagePoisoned(page))
130		pr_warn("page:%p is uninitialized and poisoned", page);
131	else
132		__dump_page(page);
133	if (reason)
134		pr_warn("page dumped because: %s\n", reason);
135	dump_page_owner(page);
136}
137EXPORT_SYMBOL(dump_page);
138
139#ifdef CONFIG_DEBUG_VM
140
141void dump_vma(const struct vm_area_struct *vma)
142{
143	pr_emerg("vma %px start %px end %px mm %px\n"
144		"prot %lx anon_vma %px vm_ops %px\n"
145		"pgoff %lx file %px private_data %px\n"
146		"flags: %#lx(%pGv)\n",
147		vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
148		(unsigned long)pgprot_val(vma->vm_page_prot),
149		vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
150		vma->vm_file, vma->vm_private_data,
151		vma->vm_flags, &vma->vm_flags);
152}
153EXPORT_SYMBOL(dump_vma);
154
155void dump_mm(const struct mm_struct *mm)
156{
157	pr_emerg("mm %px task_size %lu\n"
158#ifdef CONFIG_MMU
159		"get_unmapped_area %px\n"
160#endif
161		"mmap_base %lu mmap_legacy_base %lu\n"
162		"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
163		"hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
164		"pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
165		"start_code %lx end_code %lx start_data %lx end_data %lx\n"
166		"start_brk %lx brk %lx start_stack %lx\n"
167		"arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
168		"binfmt %px flags %lx\n"
169#ifdef CONFIG_AIO
170		"ioctx_table %px\n"
171#endif
172#ifdef CONFIG_MEMCG
173		"owner %px "
174#endif
175		"exe_file %px\n"
176#ifdef CONFIG_MMU_NOTIFIER
177		"notifier_subscriptions %px\n"
178#endif
179#ifdef CONFIG_NUMA_BALANCING
180		"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
181#endif
182		"tlb_flush_pending %d\n"
183		"def_flags: %#lx(%pGv)\n",
184
185		mm, mm->task_size,
186#ifdef CONFIG_MMU
187		mm->get_unmapped_area,
188#endif
189		mm->mmap_base, mm->mmap_legacy_base,
190		mm->pgd, atomic_read(&mm->mm_users),
191		atomic_read(&mm->mm_count),
192		mm_pgtables_bytes(mm),
193		mm->map_count,
194		mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
195		(u64)atomic64_read(&mm->pinned_vm),
196		mm->data_vm, mm->exec_vm, mm->stack_vm,
197		mm->start_code, mm->end_code, mm->start_data, mm->end_data,
198		mm->start_brk, mm->brk, mm->start_stack,
199		mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
200		mm->binfmt, mm->flags,
201#ifdef CONFIG_AIO
202		mm->ioctx_table,
203#endif
204#ifdef CONFIG_MEMCG
205		mm->owner,
206#endif
207		mm->exe_file,
208#ifdef CONFIG_MMU_NOTIFIER
209		mm->notifier_subscriptions,
210#endif
211#ifdef CONFIG_NUMA_BALANCING
212		mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
213#endif
214		atomic_read(&mm->tlb_flush_pending),
215		mm->def_flags, &mm->def_flags
216	);
217}
218
219static bool page_init_poisoning __read_mostly = true;
220
221static int __init setup_vm_debug(char *str)
222{
223	bool __page_init_poisoning = true;
224
225	/*
226	 * Calling vm_debug with no arguments is equivalent to requesting
227	 * to enable all debugging options we can control.
228	 */
229	if (*str++ != '=' || !*str)
230		goto out;
231
232	__page_init_poisoning = false;
233	if (*str == '-')
234		goto out;
235
236	while (*str) {
237		switch (tolower(*str)) {
238		case'p':
239			__page_init_poisoning = true;
240			break;
241		default:
242			pr_err("vm_debug option '%c' unknown. skipped\n",
243			       *str);
244		}
245
246		str++;
247	}
248out:
249	if (page_init_poisoning && !__page_init_poisoning)
250		pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
251
252	page_init_poisoning = __page_init_poisoning;
253
254	return 1;
255}
256__setup("vm_debug", setup_vm_debug);
257
258void page_init_poison(struct page *page, size_t size)
259{
260	if (page_init_poisoning)
261		memset(page, PAGE_POISON_PATTERN, size);
262}
263#endif		/* CONFIG_DEBUG_VM */