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