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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 */
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
20const char *migrate_reason_names[MR_TYPES] = {
21 "compaction",
22 "memory_failure",
23 "memory_hotplug",
24 "syscall_or_cpuset",
25 "mempolicy_mbind",
26 "numa_misplaced",
27 "contig_range",
28 "longterm_pin",
29};
30
31const struct trace_print_flags pageflag_names[] = {
32 __def_pageflag_names,
33 {0, NULL}
34};
35
36const struct trace_print_flags gfpflag_names[] = {
37 __def_gfpflag_names,
38 {0, NULL}
39};
40
41const struct trace_print_flags vmaflag_names[] = {
42 __def_vmaflag_names,
43 {0, NULL}
44};
45
46static void __dump_page(struct page *page)
47{
48 struct page *head = compound_head(page);
49 struct address_space *mapping;
50 bool compound = PageCompound(page);
51 /*
52 * Accessing the pageblock without the zone lock. It could change to
53 * "isolate" again in the meantime, but since we are just dumping the
54 * state for debugging, it should be fine to accept a bit of
55 * inaccuracy here due to racing.
56 */
57 bool page_cma = is_migrate_cma_page(page);
58 int mapcount;
59 char *type = "";
60
61 if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
62 /*
63 * Corrupt page, so we cannot call page_mapping. Instead, do a
64 * safe subset of the steps that page_mapping() does. Caution:
65 * this will be misleading for tail pages, PageSwapCache pages,
66 * and potentially other situations. (See the page_mapping()
67 * implementation for what's missing here.)
68 */
69 unsigned long tmp = (unsigned long)page->mapping;
70
71 if (tmp & PAGE_MAPPING_ANON)
72 mapping = NULL;
73 else
74 mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
75 head = page;
76 compound = false;
77 } else {
78 mapping = page_mapping(page);
79 }
80
81 /*
82 * Avoid VM_BUG_ON() in page_mapcount().
83 * page->_mapcount space in struct page is used by sl[aou]b pages to
84 * encode own info.
85 */
86 mapcount = PageSlab(head) ? 0 : page_mapcount(page);
87
88 pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
89 page, page_ref_count(head), mapcount, mapping,
90 page_to_pgoff(page), page_to_pfn(page));
91 if (compound) {
92 if (hpage_pincount_available(page)) {
93 pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
94 head, compound_order(head),
95 head_compound_mapcount(head),
96 head_compound_pincount(head));
97 } else {
98 pr_warn("head:%p order:%u compound_mapcount:%d\n",
99 head, compound_order(head),
100 head_compound_mapcount(head));
101 }
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 struct inode *host;
114 const struct address_space_operations *a_ops;
115 struct hlist_node *dentry_first;
116 struct dentry *dentry_ptr;
117 struct dentry dentry;
118 unsigned long ino;
119
120 /*
121 * mapping can be invalid pointer and we don't want to crash
122 * accessing it, so probe everything depending on it carefully
123 */
124 if (get_kernel_nofault(host, &mapping->host) ||
125 get_kernel_nofault(a_ops, &mapping->a_ops)) {
126 pr_warn("failed to read mapping contents, not a valid kernel address?\n");
127 goto out_mapping;
128 }
129
130 if (!host) {
131 pr_warn("aops:%ps\n", a_ops);
132 goto out_mapping;
133 }
134
135 if (get_kernel_nofault(dentry_first, &host->i_dentry.first) ||
136 get_kernel_nofault(ino, &host->i_ino)) {
137 pr_warn("aops:%ps with invalid host inode %px\n",
138 a_ops, host);
139 goto out_mapping;
140 }
141
142 if (!dentry_first) {
143 pr_warn("aops:%ps ino:%lx\n", a_ops, ino);
144 goto out_mapping;
145 }
146
147 dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
148 if (get_kernel_nofault(dentry, dentry_ptr)) {
149 pr_warn("aops:%ps ino:%lx with invalid dentry %px\n",
150 a_ops, ino, dentry_ptr);
151 } else {
152 /*
153 * if dentry is corrupted, the %pd handler may still
154 * crash, but it's unlikely that we reach here with a
155 * corrupted struct page
156 */
157 pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
158 a_ops, ino, &dentry);
159 }
160 }
161out_mapping:
162 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
163
164 pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
165 page_cma ? " CMA" : "");
166 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
167 sizeof(unsigned long), page,
168 sizeof(struct page), false);
169 if (head != page)
170 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
171 sizeof(unsigned long), head,
172 sizeof(struct page), false);
173}
174
175void dump_page(struct page *page, const char *reason)
176{
177 if (PagePoisoned(page))
178 pr_warn("page:%p is uninitialized and poisoned", page);
179 else
180 __dump_page(page);
181 if (reason)
182 pr_warn("page dumped because: %s\n", reason);
183 dump_page_owner(page);
184}
185EXPORT_SYMBOL(dump_page);
186
187#ifdef CONFIG_DEBUG_VM
188
189void dump_vma(const struct vm_area_struct *vma)
190{
191 pr_emerg("vma %px start %px end %px\n"
192 "next %px prev %px mm %px\n"
193 "prot %lx anon_vma %px vm_ops %px\n"
194 "pgoff %lx file %px private_data %px\n"
195 "flags: %#lx(%pGv)\n",
196 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
197 vma->vm_prev, vma->vm_mm,
198 (unsigned long)pgprot_val(vma->vm_page_prot),
199 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
200 vma->vm_file, vma->vm_private_data,
201 vma->vm_flags, &vma->vm_flags);
202}
203EXPORT_SYMBOL(dump_vma);
204
205void dump_mm(const struct mm_struct *mm)
206{
207 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
208#ifdef CONFIG_MMU
209 "get_unmapped_area %px\n"
210#endif
211 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
212 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
213 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
214 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
215 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
216 "start_brk %lx brk %lx start_stack %lx\n"
217 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
218 "binfmt %px flags %lx core_state %px\n"
219#ifdef CONFIG_AIO
220 "ioctx_table %px\n"
221#endif
222#ifdef CONFIG_MEMCG
223 "owner %px "
224#endif
225 "exe_file %px\n"
226#ifdef CONFIG_MMU_NOTIFIER
227 "notifier_subscriptions %px\n"
228#endif
229#ifdef CONFIG_NUMA_BALANCING
230 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
231#endif
232 "tlb_flush_pending %d\n"
233 "def_flags: %#lx(%pGv)\n",
234
235 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
236#ifdef CONFIG_MMU
237 mm->get_unmapped_area,
238#endif
239 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
240 mm->pgd, atomic_read(&mm->mm_users),
241 atomic_read(&mm->mm_count),
242 mm_pgtables_bytes(mm),
243 mm->map_count,
244 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
245 (u64)atomic64_read(&mm->pinned_vm),
246 mm->data_vm, mm->exec_vm, mm->stack_vm,
247 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
248 mm->start_brk, mm->brk, mm->start_stack,
249 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
250 mm->binfmt, mm->flags, mm->core_state,
251#ifdef CONFIG_AIO
252 mm->ioctx_table,
253#endif
254#ifdef CONFIG_MEMCG
255 mm->owner,
256#endif
257 mm->exe_file,
258#ifdef CONFIG_MMU_NOTIFIER
259 mm->notifier_subscriptions,
260#endif
261#ifdef CONFIG_NUMA_BALANCING
262 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
263#endif
264 atomic_read(&mm->tlb_flush_pending),
265 mm->def_flags, &mm->def_flags
266 );
267}
268
269static bool page_init_poisoning __read_mostly = true;
270
271static int __init setup_vm_debug(char *str)
272{
273 bool __page_init_poisoning = true;
274
275 /*
276 * Calling vm_debug with no arguments is equivalent to requesting
277 * to enable all debugging options we can control.
278 */
279 if (*str++ != '=' || !*str)
280 goto out;
281
282 __page_init_poisoning = false;
283 if (*str == '-')
284 goto out;
285
286 while (*str) {
287 switch (tolower(*str)) {
288 case'p':
289 __page_init_poisoning = true;
290 break;
291 default:
292 pr_err("vm_debug option '%c' unknown. skipped\n",
293 *str);
294 }
295
296 str++;
297 }
298out:
299 if (page_init_poisoning && !__page_init_poisoning)
300 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
301
302 page_init_poisoning = __page_init_poisoning;
303
304 return 1;
305}
306__setup("vm_debug", setup_vm_debug);
307
308void page_init_poison(struct page *page, size_t size)
309{
310 if (page_init_poisoning)
311 memset(page, PAGE_POISON_PATTERN, size);
312}
313EXPORT_SYMBOL_GPL(page_init_poison);
314#endif /* CONFIG_DEBUG_VM */