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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
31c9afa6 SL |
2 | /* |
3 | * mm/debug.c | |
4 | * | |
5 | * mm/ specific debug routines. | |
6 | * | |
7 | */ | |
8 | ||
82742a3a SL |
9 | #include <linux/kernel.h> |
10 | #include <linux/mm.h> | |
af658dca | 11 | #include <linux/trace_events.h> |
82742a3a | 12 | #include <linux/memcontrol.h> |
420adbe9 | 13 | #include <trace/events/mmflags.h> |
7cd12b4a | 14 | #include <linux/migrate.h> |
4e462112 | 15 | #include <linux/page_owner.h> |
f682a97a | 16 | #include <linux/ctype.h> |
82742a3a | 17 | |
edf14cdb VB |
18 | #include "internal.h" |
19 | ||
9a2f45ff | 20 | const char *migrate_reason_names[MR_TYPES] = { |
7cd12b4a VB |
21 | "compaction", |
22 | "memory_failure", | |
23 | "memory_hotplug", | |
24 | "syscall_or_cpuset", | |
25 | "mempolicy_mbind", | |
26 | "numa_misplaced", | |
27 | "cma", | |
28 | }; | |
29 | ||
edf14cdb VB |
30 | const struct trace_print_flags pageflag_names[] = { |
31 | __def_pageflag_names, | |
32 | {0, NULL} | |
33 | }; | |
34 | ||
35 | const struct trace_print_flags gfpflag_names[] = { | |
36 | __def_gfpflag_names, | |
37 | {0, NULL} | |
420adbe9 VB |
38 | }; |
39 | ||
edf14cdb VB |
40 | const struct trace_print_flags vmaflag_names[] = { |
41 | __def_vmaflag_names, | |
42 | {0, NULL} | |
82742a3a SL |
43 | }; |
44 | ||
ff8e8116 | 45 | void __dump_page(struct page *page, const char *reason) |
82742a3a | 46 | { |
6197ab98 | 47 | struct page *head = compound_head(page); |
311ade0e | 48 | struct address_space *mapping; |
fc36def9 | 49 | bool page_poisoned = PagePoisoned(page); |
6197ab98 | 50 | bool compound = PageCompound(page); |
4a55c047 QC |
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); | |
fc36def9 | 58 | int mapcount; |
5b57b8f2 | 59 | char *type = ""; |
fc36def9 PT |
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) { | |
e0392cf7 | 67 | pr_warn("page:%px is uninitialized and poisoned", page); |
fc36def9 PT |
68 | goto hex_only; |
69 | } | |
70 | ||
6197ab98 | 71 | if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) { |
e1ab96f8 MWO |
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); | |
6197ab98 MWO |
85 | head = page; |
86 | compound = false; | |
87 | } else { | |
88 | mapping = page_mapping(page); | |
89 | } | |
311ade0e | 90 | |
9996f05e KS |
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 | */ | |
6197ab98 MWO |
96 | mapcount = PageSlab(head) ? 0 : page_mapcount(page); |
97 | ||
54a75157 | 98 | pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n", |
452b557c | 99 | page, page_ref_count(head), mapcount, mapping, |
54a75157 | 100 | page_to_pgoff(page), page_to_pfn(page)); |
452b557c | 101 | if (compound) { |
dc8fb2f2 | 102 | if (hpage_pincount_available(page)) { |
54a75157 | 103 | pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n", |
452b557c | 104 | head, compound_order(head), |
6dc5ea16 JH |
105 | head_mapcount(head), |
106 | head_pincount(head)); | |
dc8fb2f2 | 107 | } else { |
54a75157 | 108 | pr_warn("head:%p order:%u compound_mapcount:%d\n", |
452b557c | 109 | head, compound_order(head), |
6dc5ea16 | 110 | head_mapcount(head)); |
dc8fb2f2 | 111 | } |
452b557c | 112 | } |
6855ac4a | 113 | if (PageKsm(page)) |
5b57b8f2 | 114 | type = "ksm "; |
6855ac4a | 115 | else if (PageAnon(page)) |
5b57b8f2 | 116 | type = "anon "; |
1c6fb1d8 | 117 | else if (mapping) { |
9ad38265 | 118 | struct inode *host; |
002ae705 | 119 | const struct address_space_operations *a_ops; |
9ad38265 MWO |
120 | struct hlist_node *dentry_first; |
121 | struct dentry *dentry_ptr; | |
002ae705 VB |
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 | */ | |
9ad38265 MWO |
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"); | |
002ae705 VB |
131 | goto out_mapping; |
132 | } | |
133 | ||
134 | if (!host) { | |
9ad38265 | 135 | pr_warn("aops:%ps\n", a_ops); |
002ae705 VB |
136 | goto out_mapping; |
137 | } | |
138 | ||
9ad38265 MWO |
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); | |
002ae705 VB |
142 | goto out_mapping; |
143 | } | |
144 | ||
145 | if (!dentry_first) { | |
9bdaf2cc | 146 | pr_warn("aops:%ps ino:%lx\n", a_ops, host->i_ino); |
002ae705 VB |
147 | goto out_mapping; |
148 | } | |
149 | ||
150 | dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias); | |
9ad38265 MWO |
151 | if (get_kernel_nofault(dentry, dentry_ptr)) { |
152 | pr_warn("aops:%ps with invalid dentry %px\n", a_ops, | |
153 | dentry_ptr); | |
002ae705 VB |
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 | */ | |
9bdaf2cc MWO |
160 | pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", |
161 | a_ops, host->i_ino, &dentry); | |
002ae705 | 162 | } |
1c6fb1d8 | 163 | } |
002ae705 | 164 | out_mapping: |
edf14cdb | 165 | BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); |
ff8e8116 | 166 | |
0b93d59e | 167 | pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags, |
4a55c047 | 168 | page_cma ? " CMA" : ""); |
5b57b8f2 | 169 | |
fc36def9 | 170 | hex_only: |
e0392cf7 | 171 | print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32, |
46e8a3a0 VB |
172 | sizeof(unsigned long), page, |
173 | sizeof(struct page), false); | |
6197ab98 MWO |
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); | |
46e8a3a0 | 178 | |
82742a3a | 179 | if (reason) |
e0392cf7 | 180 | pr_warn("page dumped because: %s\n", reason); |
b8eceeb9 | 181 | |
9edad6ea | 182 | #ifdef CONFIG_MEMCG |
fc36def9 | 183 | if (!page_poisoned && page->mem_cgroup) |
e0392cf7 | 184 | pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup); |
9edad6ea | 185 | #endif |
82742a3a SL |
186 | } |
187 | ||
188 | void dump_page(struct page *page, const char *reason) | |
189 | { | |
ff8e8116 | 190 | __dump_page(page, reason); |
4e462112 | 191 | dump_page_owner(page); |
82742a3a SL |
192 | } |
193 | EXPORT_SYMBOL(dump_page); | |
194 | ||
195 | #ifdef CONFIG_DEBUG_VM | |
196 | ||
82742a3a SL |
197 | void dump_vma(const struct vm_area_struct *vma) |
198 | { | |
152a2d19 MW |
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" | |
b8eceeb9 | 203 | "flags: %#lx(%pGv)\n", |
82742a3a SL |
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, | |
b8eceeb9 VB |
208 | vma->vm_file, vma->vm_private_data, |
209 | vma->vm_flags, &vma->vm_flags); | |
82742a3a SL |
210 | } |
211 | EXPORT_SYMBOL(dump_vma); | |
212 | ||
31c9afa6 SL |
213 | void dump_mm(const struct mm_struct *mm) |
214 | { | |
7a9cdebd | 215 | pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n" |
31c9afa6 | 216 | #ifdef CONFIG_MMU |
152a2d19 | 217 | "get_unmapped_area %px\n" |
31c9afa6 SL |
218 | #endif |
219 | "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n" | |
152a2d19 | 220 | "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n" |
31c9afa6 | 221 | "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" |
70f8a3ca | 222 | "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n" |
31c9afa6 SL |
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" | |
152a2d19 | 226 | "binfmt %px flags %lx core_state %px\n" |
31c9afa6 | 227 | #ifdef CONFIG_AIO |
152a2d19 | 228 | "ioctx_table %px\n" |
31c9afa6 SL |
229 | #endif |
230 | #ifdef CONFIG_MEMCG | |
152a2d19 | 231 | "owner %px " |
31c9afa6 | 232 | #endif |
152a2d19 | 233 | "exe_file %px\n" |
31c9afa6 | 234 | #ifdef CONFIG_MMU_NOTIFIER |
984cfe4e | 235 | "notifier_subscriptions %px\n" |
31c9afa6 SL |
236 | #endif |
237 | #ifdef CONFIG_NUMA_BALANCING | |
238 | "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n" | |
239 | #endif | |
31c9afa6 | 240 | "tlb_flush_pending %d\n" |
b8eceeb9 | 241 | "def_flags: %#lx(%pGv)\n", |
31c9afa6 | 242 | |
7a9cdebd | 243 | mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size, |
31c9afa6 SL |
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), | |
af5b0f6a | 250 | mm_pgtables_bytes(mm), |
31c9afa6 SL |
251 | mm->map_count, |
252 | mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, | |
44dc1b1f | 253 | (u64)atomic64_read(&mm->pinned_vm), |
70f8a3ca | 254 | mm->data_vm, mm->exec_vm, mm->stack_vm, |
31c9afa6 SL |
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 | |
984cfe4e | 267 | mm->notifier_subscriptions, |
31c9afa6 SL |
268 | #endif |
269 | #ifdef CONFIG_NUMA_BALANCING | |
270 | mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq, | |
271 | #endif | |
16af97dc | 272 | atomic_read(&mm->tlb_flush_pending), |
b8eceeb9 VB |
273 | mm->def_flags, &mm->def_flags |
274 | ); | |
31c9afa6 SL |
275 | } |
276 | ||
f682a97a AD |
277 | static bool page_init_poisoning __read_mostly = true; |
278 | ||
279 | static 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 | } | |
306 | out: | |
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 | ||
316 | void page_init_poison(struct page *page, size_t size) | |
317 | { | |
318 | if (page_init_poisoning) | |
319 | memset(page, PAGE_POISON_PATTERN, size); | |
320 | } | |
321 | EXPORT_SYMBOL_GPL(page_init_poison); | |
82742a3a | 322 | #endif /* CONFIG_DEBUG_VM */ |