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 pagetype_names[] = {
40	__def_pagetype_names,
41	{0, NULL}
42};
43
44const struct trace_print_flags gfpflag_names[] = {
45	__def_gfpflag_names,
46	{0, NULL}
47};
48
49const struct trace_print_flags vmaflag_names[] = {
50	__def_vmaflag_names,
51	{0, NULL}
52};
53
54static void __dump_folio(struct folio *folio, struct page *page,
55		unsigned long pfn, unsigned long idx)
56{
57	struct address_space *mapping = folio_mapping(folio);
58	int mapcount = 0;
59	char *type = "";
60
61	/*
62	 * page->_mapcount space in struct page is used by slab pages to
63	 * encode own info, and we must avoid calling page_folio() again.
64	 */
65	if (!folio_test_slab(folio)) {
66		mapcount = atomic_read(&page->_mapcount) + 1;
67		if (folio_test_large(folio))
68			mapcount += folio_entire_mapcount(folio);
69	}
70
71	pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
72			folio_ref_count(folio), mapcount, mapping,
73			folio->index + idx, pfn);
74	if (folio_test_large(folio)) {
75		pr_warn("head: order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
76				folio_order(folio),
77				folio_entire_mapcount(folio),
78				folio_nr_pages_mapped(folio),
79				atomic_read(&folio->_pincount));
80	}
81
82#ifdef CONFIG_MEMCG
83	if (folio->memcg_data)
84		pr_warn("memcg:%lx\n", folio->memcg_data);
85#endif
86	if (folio_test_ksm(folio))
87		type = "ksm ";
88	else if (folio_test_anon(folio))
89		type = "anon ";
90	else if (mapping)
91		dump_mapping(mapping);
92	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
93
94	/*
95	 * Accessing the pageblock without the zone lock. It could change to
96	 * "isolate" again in the meantime, but since we are just dumping the
97	 * state for debugging, it should be fine to accept a bit of
98	 * inaccuracy here due to racing.
99	 */
100	pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
101		is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
102	pr_warn("page_type: %pGt\n", &folio->page.page_type);
103
104	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
105			sizeof(unsigned long), page,
106			sizeof(struct page), false);
107	if (folio_test_large(folio))
108		print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
109			sizeof(unsigned long), folio,
110			2 * sizeof(struct page), false);
111}
112
113static void __dump_page(const struct page *page)
114{
115	struct folio *foliop, folio;
116	struct page precise;
117	unsigned long pfn = page_to_pfn(page);
118	unsigned long idx, nr_pages = 1;
119	int loops = 5;
120
121again:
122	memcpy(&precise, page, sizeof(*page));
123	foliop = page_folio(&precise);
124	if (foliop == (struct folio *)&precise) {
125		idx = 0;
126		if (!folio_test_large(foliop))
127			goto dump;
128		foliop = (struct folio *)page;
129	} else {
130		idx = folio_page_idx(foliop, page);
131	}
132
133	if (idx < MAX_FOLIO_NR_PAGES) {
134		memcpy(&folio, foliop, 2 * sizeof(struct page));
135		nr_pages = folio_nr_pages(&folio);
136		foliop = &folio;
137	}
138
139	if (idx > nr_pages) {
140		if (loops-- > 0)
141			goto again;
142		pr_warn("page does not match folio\n");
143		precise.compound_head &= ~1UL;
144		foliop = (struct folio *)&precise;
145		idx = 0;
146	}
147
148dump:
149	__dump_folio(foliop, &precise, pfn, idx);
150}
151
152void dump_page(const struct page *page, const char *reason)
153{
154	if (PagePoisoned(page))
155		pr_warn("page:%p is uninitialized and poisoned", page);
156	else
157		__dump_page(page);
158	if (reason)
159		pr_warn("page dumped because: %s\n", reason);
160	dump_page_owner(page);
161}
162EXPORT_SYMBOL(dump_page);
163
164#ifdef CONFIG_DEBUG_VM
165
166void dump_vma(const struct vm_area_struct *vma)
167{
168	pr_emerg("vma %px start %px end %px mm %px\n"
169		"prot %lx anon_vma %px vm_ops %px\n"
170		"pgoff %lx file %px private_data %px\n"
171		"flags: %#lx(%pGv)\n",
172		vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
173		(unsigned long)pgprot_val(vma->vm_page_prot),
174		vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
175		vma->vm_file, vma->vm_private_data,
176		vma->vm_flags, &vma->vm_flags);
177}
178EXPORT_SYMBOL(dump_vma);
179
180void dump_mm(const struct mm_struct *mm)
181{
182	pr_emerg("mm %px task_size %lu\n"
183#ifdef CONFIG_MMU
184		"get_unmapped_area %px\n"
185#endif
186		"mmap_base %lu mmap_legacy_base %lu\n"
187		"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
188		"hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
189		"pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
190		"start_code %lx end_code %lx start_data %lx end_data %lx\n"
191		"start_brk %lx brk %lx start_stack %lx\n"
192		"arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
193		"binfmt %px flags %lx\n"
194#ifdef CONFIG_AIO
195		"ioctx_table %px\n"
196#endif
197#ifdef CONFIG_MEMCG
198		"owner %px "
199#endif
200		"exe_file %px\n"
201#ifdef CONFIG_MMU_NOTIFIER
202		"notifier_subscriptions %px\n"
203#endif
204#ifdef CONFIG_NUMA_BALANCING
205		"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
206#endif
207		"tlb_flush_pending %d\n"
208		"def_flags: %#lx(%pGv)\n",
209
210		mm, mm->task_size,
211#ifdef CONFIG_MMU
212		mm->get_unmapped_area,
213#endif
214		mm->mmap_base, mm->mmap_legacy_base,
215		mm->pgd, atomic_read(&mm->mm_users),
216		atomic_read(&mm->mm_count),
217		mm_pgtables_bytes(mm),
218		mm->map_count,
219		mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
220		(u64)atomic64_read(&mm->pinned_vm),
221		mm->data_vm, mm->exec_vm, mm->stack_vm,
222		mm->start_code, mm->end_code, mm->start_data, mm->end_data,
223		mm->start_brk, mm->brk, mm->start_stack,
224		mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
225		mm->binfmt, mm->flags,
226#ifdef CONFIG_AIO
227		mm->ioctx_table,
228#endif
229#ifdef CONFIG_MEMCG
230		mm->owner,
231#endif
232		mm->exe_file,
233#ifdef CONFIG_MMU_NOTIFIER
234		mm->notifier_subscriptions,
235#endif
236#ifdef CONFIG_NUMA_BALANCING
237		mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
238#endif
239		atomic_read(&mm->tlb_flush_pending),
240		mm->def_flags, &mm->def_flags
241	);
242}
243EXPORT_SYMBOL(dump_mm);
244
245static bool page_init_poisoning __read_mostly = true;
246
247static int __init setup_vm_debug(char *str)
248{
249	bool __page_init_poisoning = true;
250
251	/*
252	 * Calling vm_debug with no arguments is equivalent to requesting
253	 * to enable all debugging options we can control.
254	 */
255	if (*str++ != '=' || !*str)
256		goto out;
257
258	__page_init_poisoning = false;
259	if (*str == '-')
260		goto out;
261
262	while (*str) {
263		switch (tolower(*str)) {
264		case'p':
265			__page_init_poisoning = true;
266			break;
267		default:
268			pr_err("vm_debug option '%c' unknown. skipped\n",
269			       *str);
270		}
271
272		str++;
273	}
274out:
275	if (page_init_poisoning && !__page_init_poisoning)
276		pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
277
278	page_init_poisoning = __page_init_poisoning;
279
280	return 1;
281}
282__setup("vm_debug", setup_vm_debug);
283
284void page_init_poison(struct page *page, size_t size)
285{
286	if (page_init_poisoning)
287		memset(page, PAGE_POISON_PATTERN, size);
288}
289
290void vma_iter_dump_tree(const struct vma_iterator *vmi)
291{
292#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
293	mas_dump(&vmi->mas);
294	mt_dump(vmi->mas.tree, mt_dump_hex);
295#endif	/* CONFIG_DEBUG_VM_MAPLE_TREE */
296}
297
298#endif		/* CONFIG_DEBUG_VM */
299