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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
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 "cma",
28};
29
30const struct trace_print_flags pageflag_names[] = {
31 __def_pageflag_names,
32 {0, NULL}
33};
34
35const struct trace_print_flags gfpflag_names[] = {
36 __def_gfpflag_names,
37 {0, NULL}
38};
39
40const struct trace_print_flags vmaflag_names[] = {
41 __def_vmaflag_names,
42 {0, NULL}
43};
44
45void __dump_page(struct page *page, const char *reason)
46{
47 struct address_space *mapping;
48 bool page_poisoned = PagePoisoned(page);
49 int mapcount;
50
51 /*
52 * If struct page is poisoned don't access Page*() functions as that
53 * leads to recursive loop. Page*() check for poisoned pages, and calls
54 * dump_page() when detected.
55 */
56 if (page_poisoned) {
57 pr_warn("page:%px is uninitialized and poisoned", page);
58 goto hex_only;
59 }
60
61 mapping = page_mapping(page);
62
63 /*
64 * Avoid VM_BUG_ON() in page_mapcount().
65 * page->_mapcount space in struct page is used by sl[aou]b pages to
66 * encode own info.
67 */
68 mapcount = PageSlab(page) ? 0 : page_mapcount(page);
69
70 if (PageCompound(page))
71 pr_warn("page:%px refcount:%d mapcount:%d mapping:%px "
72 "index:%#lx compound_mapcount: %d\n",
73 page, page_ref_count(page), mapcount,
74 page->mapping, page_to_pgoff(page),
75 compound_mapcount(page));
76 else
77 pr_warn("page:%px refcount:%d mapcount:%d mapping:%px index:%#lx\n",
78 page, page_ref_count(page), mapcount,
79 page->mapping, page_to_pgoff(page));
80 if (PageKsm(page))
81 pr_warn("ksm flags: %#lx(%pGp)\n", page->flags, &page->flags);
82 else if (PageAnon(page))
83 pr_warn("anon flags: %#lx(%pGp)\n", page->flags, &page->flags);
84 else if (mapping) {
85 if (mapping->host && mapping->host->i_dentry.first) {
86 struct dentry *dentry;
87 dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
88 pr_warn("%ps name:\"%pd\"\n", mapping->a_ops, dentry);
89 } else
90 pr_warn("%ps\n", mapping->a_ops);
91 pr_warn("flags: %#lx(%pGp)\n", page->flags, &page->flags);
92 }
93 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
94
95hex_only:
96 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
97 sizeof(unsigned long), page,
98 sizeof(struct page), false);
99
100 if (reason)
101 pr_warn("page dumped because: %s\n", reason);
102
103#ifdef CONFIG_MEMCG
104 if (!page_poisoned && page->mem_cgroup)
105 pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
106#endif
107}
108
109void dump_page(struct page *page, const char *reason)
110{
111 __dump_page(page, reason);
112 dump_page_owner(page);
113}
114EXPORT_SYMBOL(dump_page);
115
116#ifdef CONFIG_DEBUG_VM
117
118void dump_vma(const struct vm_area_struct *vma)
119{
120 pr_emerg("vma %px start %px end %px\n"
121 "next %px prev %px mm %px\n"
122 "prot %lx anon_vma %px vm_ops %px\n"
123 "pgoff %lx file %px private_data %px\n"
124 "flags: %#lx(%pGv)\n",
125 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
126 vma->vm_prev, vma->vm_mm,
127 (unsigned long)pgprot_val(vma->vm_page_prot),
128 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
129 vma->vm_file, vma->vm_private_data,
130 vma->vm_flags, &vma->vm_flags);
131}
132EXPORT_SYMBOL(dump_vma);
133
134void dump_mm(const struct mm_struct *mm)
135{
136 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
137#ifdef CONFIG_MMU
138 "get_unmapped_area %px\n"
139#endif
140 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
141 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
142 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
143 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
144 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
145 "start_brk %lx brk %lx start_stack %lx\n"
146 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
147 "binfmt %px flags %lx core_state %px\n"
148#ifdef CONFIG_AIO
149 "ioctx_table %px\n"
150#endif
151#ifdef CONFIG_MEMCG
152 "owner %px "
153#endif
154 "exe_file %px\n"
155#ifdef CONFIG_MMU_NOTIFIER
156 "mmu_notifier_mm %px\n"
157#endif
158#ifdef CONFIG_NUMA_BALANCING
159 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
160#endif
161 "tlb_flush_pending %d\n"
162 "def_flags: %#lx(%pGv)\n",
163
164 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
165#ifdef CONFIG_MMU
166 mm->get_unmapped_area,
167#endif
168 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
169 mm->pgd, atomic_read(&mm->mm_users),
170 atomic_read(&mm->mm_count),
171 mm_pgtables_bytes(mm),
172 mm->map_count,
173 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
174 (u64)atomic64_read(&mm->pinned_vm),
175 mm->data_vm, mm->exec_vm, mm->stack_vm,
176 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
177 mm->start_brk, mm->brk, mm->start_stack,
178 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
179 mm->binfmt, mm->flags, mm->core_state,
180#ifdef CONFIG_AIO
181 mm->ioctx_table,
182#endif
183#ifdef CONFIG_MEMCG
184 mm->owner,
185#endif
186 mm->exe_file,
187#ifdef CONFIG_MMU_NOTIFIER
188 mm->mmu_notifier_mm,
189#endif
190#ifdef CONFIG_NUMA_BALANCING
191 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
192#endif
193 atomic_read(&mm->tlb_flush_pending),
194 mm->def_flags, &mm->def_flags
195 );
196}
197
198static bool page_init_poisoning __read_mostly = true;
199
200static int __init setup_vm_debug(char *str)
201{
202 bool __page_init_poisoning = true;
203
204 /*
205 * Calling vm_debug with no arguments is equivalent to requesting
206 * to enable all debugging options we can control.
207 */
208 if (*str++ != '=' || !*str)
209 goto out;
210
211 __page_init_poisoning = false;
212 if (*str == '-')
213 goto out;
214
215 while (*str) {
216 switch (tolower(*str)) {
217 case'p':
218 __page_init_poisoning = true;
219 break;
220 default:
221 pr_err("vm_debug option '%c' unknown. skipped\n",
222 *str);
223 }
224
225 str++;
226 }
227out:
228 if (page_init_poisoning && !__page_init_poisoning)
229 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
230
231 page_init_poisoning = __page_init_poisoning;
232
233 return 1;
234}
235__setup("vm_debug", setup_vm_debug);
236
237void page_init_poison(struct page *page, size_t size)
238{
239 if (page_init_poisoning)
240 memset(page, PAGE_POISON_PATTERN, size);
241}
242EXPORT_SYMBOL_GPL(page_init_poison);
243#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 "cma",
28};
29
30const struct trace_print_flags pageflag_names[] = {
31 __def_pageflag_names,
32 {0, NULL}
33};
34
35const struct trace_print_flags gfpflag_names[] = {
36 __def_gfpflag_names,
37 {0, NULL}
38};
39
40const struct trace_print_flags vmaflag_names[] = {
41 __def_vmaflag_names,
42 {0, NULL}
43};
44
45void __dump_page(struct page *page, const char *reason)
46{
47 struct page *head = compound_head(page);
48 struct address_space *mapping;
49 bool page_poisoned = PagePoisoned(page);
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 /*
62 * If struct page is poisoned don't access Page*() functions as that
63 * leads to recursive loop. Page*() check for poisoned pages, and calls
64 * dump_page() when detected.
65 */
66 if (page_poisoned) {
67 pr_warn("page:%px is uninitialized and poisoned", page);
68 goto hex_only;
69 }
70
71 if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
72 /*
73 * Corrupt page, so we cannot call page_mapping. Instead, do a
74 * safe subset of the steps that page_mapping() does. Caution:
75 * this will be misleading for tail pages, PageSwapCache pages,
76 * and potentially other situations. (See the page_mapping()
77 * implementation for what's missing here.)
78 */
79 unsigned long tmp = (unsigned long)page->mapping;
80
81 if (tmp & PAGE_MAPPING_ANON)
82 mapping = NULL;
83 else
84 mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
85 head = page;
86 compound = false;
87 } else {
88 mapping = page_mapping(page);
89 }
90
91 /*
92 * Avoid VM_BUG_ON() in page_mapcount().
93 * page->_mapcount space in struct page is used by sl[aou]b pages to
94 * encode own info.
95 */
96 mapcount = PageSlab(head) ? 0 : page_mapcount(page);
97
98 pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
99 page, page_ref_count(head), mapcount, mapping,
100 page_to_pgoff(page), page_to_pfn(page));
101 if (compound) {
102 if (hpage_pincount_available(page)) {
103 pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
104 head, compound_order(head),
105 head_mapcount(head),
106 head_pincount(head));
107 } else {
108 pr_warn("head:%p order:%u compound_mapcount:%d\n",
109 head, compound_order(head),
110 head_mapcount(head));
111 }
112 }
113 if (PageKsm(page))
114 type = "ksm ";
115 else if (PageAnon(page))
116 type = "anon ";
117 else if (mapping) {
118 struct inode *host;
119 const struct address_space_operations *a_ops;
120 struct hlist_node *dentry_first;
121 struct dentry *dentry_ptr;
122 struct dentry dentry;
123
124 /*
125 * mapping can be invalid pointer and we don't want to crash
126 * accessing it, so probe everything depending on it carefully
127 */
128 if (get_kernel_nofault(host, &mapping->host) ||
129 get_kernel_nofault(a_ops, &mapping->a_ops)) {
130 pr_warn("failed to read mapping contents, not a valid kernel address?\n");
131 goto out_mapping;
132 }
133
134 if (!host) {
135 pr_warn("aops:%ps\n", a_ops);
136 goto out_mapping;
137 }
138
139 if (get_kernel_nofault(dentry_first, &host->i_dentry.first)) {
140 pr_warn("aops:%ps with invalid host inode %px\n",
141 a_ops, host);
142 goto out_mapping;
143 }
144
145 if (!dentry_first) {
146 pr_warn("aops:%ps ino:%lx\n", a_ops, host->i_ino);
147 goto out_mapping;
148 }
149
150 dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
151 if (get_kernel_nofault(dentry, dentry_ptr)) {
152 pr_warn("aops:%ps with invalid dentry %px\n", a_ops,
153 dentry_ptr);
154 } else {
155 /*
156 * if dentry is corrupted, the %pd handler may still
157 * crash, but it's unlikely that we reach here with a
158 * corrupted struct page
159 */
160 pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
161 a_ops, host->i_ino, &dentry);
162 }
163 }
164out_mapping:
165 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
166
167 pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags,
168 page_cma ? " CMA" : "");
169
170hex_only:
171 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
172 sizeof(unsigned long), page,
173 sizeof(struct page), false);
174 if (head != page)
175 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
176 sizeof(unsigned long), head,
177 sizeof(struct page), false);
178
179 if (reason)
180 pr_warn("page dumped because: %s\n", reason);
181
182#ifdef CONFIG_MEMCG
183 if (!page_poisoned && page->mem_cgroup)
184 pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
185#endif
186}
187
188void dump_page(struct page *page, const char *reason)
189{
190 __dump_page(page, reason);
191 dump_page_owner(page);
192}
193EXPORT_SYMBOL(dump_page);
194
195#ifdef CONFIG_DEBUG_VM
196
197void dump_vma(const struct vm_area_struct *vma)
198{
199 pr_emerg("vma %px start %px end %px\n"
200 "next %px prev %px mm %px\n"
201 "prot %lx anon_vma %px vm_ops %px\n"
202 "pgoff %lx file %px private_data %px\n"
203 "flags: %#lx(%pGv)\n",
204 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
205 vma->vm_prev, vma->vm_mm,
206 (unsigned long)pgprot_val(vma->vm_page_prot),
207 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
208 vma->vm_file, vma->vm_private_data,
209 vma->vm_flags, &vma->vm_flags);
210}
211EXPORT_SYMBOL(dump_vma);
212
213void dump_mm(const struct mm_struct *mm)
214{
215 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
216#ifdef CONFIG_MMU
217 "get_unmapped_area %px\n"
218#endif
219 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
220 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
221 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
222 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
223 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
224 "start_brk %lx brk %lx start_stack %lx\n"
225 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
226 "binfmt %px flags %lx core_state %px\n"
227#ifdef CONFIG_AIO
228 "ioctx_table %px\n"
229#endif
230#ifdef CONFIG_MEMCG
231 "owner %px "
232#endif
233 "exe_file %px\n"
234#ifdef CONFIG_MMU_NOTIFIER
235 "notifier_subscriptions %px\n"
236#endif
237#ifdef CONFIG_NUMA_BALANCING
238 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
239#endif
240 "tlb_flush_pending %d\n"
241 "def_flags: %#lx(%pGv)\n",
242
243 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
244#ifdef CONFIG_MMU
245 mm->get_unmapped_area,
246#endif
247 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
248 mm->pgd, atomic_read(&mm->mm_users),
249 atomic_read(&mm->mm_count),
250 mm_pgtables_bytes(mm),
251 mm->map_count,
252 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
253 (u64)atomic64_read(&mm->pinned_vm),
254 mm->data_vm, mm->exec_vm, mm->stack_vm,
255 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
256 mm->start_brk, mm->brk, mm->start_stack,
257 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
258 mm->binfmt, mm->flags, mm->core_state,
259#ifdef CONFIG_AIO
260 mm->ioctx_table,
261#endif
262#ifdef CONFIG_MEMCG
263 mm->owner,
264#endif
265 mm->exe_file,
266#ifdef CONFIG_MMU_NOTIFIER
267 mm->notifier_subscriptions,
268#endif
269#ifdef CONFIG_NUMA_BALANCING
270 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
271#endif
272 atomic_read(&mm->tlb_flush_pending),
273 mm->def_flags, &mm->def_flags
274 );
275}
276
277static bool page_init_poisoning __read_mostly = true;
278
279static int __init setup_vm_debug(char *str)
280{
281 bool __page_init_poisoning = true;
282
283 /*
284 * Calling vm_debug with no arguments is equivalent to requesting
285 * to enable all debugging options we can control.
286 */
287 if (*str++ != '=' || !*str)
288 goto out;
289
290 __page_init_poisoning = false;
291 if (*str == '-')
292 goto out;
293
294 while (*str) {
295 switch (tolower(*str)) {
296 case'p':
297 __page_init_poisoning = true;
298 break;
299 default:
300 pr_err("vm_debug option '%c' unknown. skipped\n",
301 *str);
302 }
303
304 str++;
305 }
306out:
307 if (page_init_poisoning && !__page_init_poisoning)
308 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
309
310 page_init_poisoning = __page_init_poisoning;
311
312 return 1;
313}
314__setup("vm_debug", setup_vm_debug);
315
316void page_init_poison(struct page *page, size_t size)
317{
318 if (page_init_poisoning)
319 memset(page, PAGE_POISON_PATTERN, size);
320}
321EXPORT_SYMBOL_GPL(page_init_poison);
322#endif /* CONFIG_DEBUG_VM */