projects/linux·blob v5.8 · refs

321 lines · 8.5 KiB

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 /* Corrupt page, cannot call page_mapping */
73 mapping = page->mapping;
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 if (compound)
88 if (hpage_pincount_available(page)) {
89 pr_warn("page:%px refcount:%d mapcount:%d mapping:%p "
90 "index:%#lx head:%px order:%u "
91 "compound_mapcount:%d compound_pincount:%d\n",
92 page, page_ref_count(head), mapcount,
93 mapping, page_to_pgoff(page), head,
94 compound_order(head), compound_mapcount(page),
95 compound_pincount(page));
96 } else {
97 pr_warn("page:%px refcount:%d mapcount:%d mapping:%p "
98 "index:%#lx head:%px order:%u "
99 "compound_mapcount:%d\n",
100 page, page_ref_count(head), mapcount,
101 mapping, page_to_pgoff(page), head,
102 compound_order(head), compound_mapcount(page));
103 }
104 else
105 pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n",
106 page, page_ref_count(page), mapcount,
107 mapping, page_to_pgoff(page));
108 if (PageKsm(page))
109 type = "ksm ";
110 else if (PageAnon(page))
111 type = "anon ";
112 else if (mapping) {
113 const struct inode *host;
114 const struct address_space_operations *a_ops;
115 const struct hlist_node *dentry_first;
116 const struct dentry *dentry_ptr;
117 struct dentry dentry;
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 (copy_from_kernel_nofault(&host, &mapping->host,
124 sizeof(struct inode *)) ||
125 copy_from_kernel_nofault(&a_ops, &mapping->a_ops,
126 sizeof(struct address_space_operations *))) {
127 pr_warn("failed to read mapping->host or a_ops, mapping not a valid kernel address?\n");
128 goto out_mapping;
129 }
130
131 if (!host) {
132 pr_warn("mapping->a_ops:%ps\n", a_ops);
133 goto out_mapping;
134 }
135
136 if (copy_from_kernel_nofault(&dentry_first,
137 &host->i_dentry.first, sizeof(struct hlist_node *))) {
138 pr_warn("mapping->a_ops:%ps with invalid mapping->host inode address %px\n",
139 a_ops, host);
140 goto out_mapping;
141 }
142
143 if (!dentry_first) {
144 pr_warn("mapping->a_ops:%ps\n", a_ops);
145 goto out_mapping;
146 }
147
148 dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias);
149 if (copy_from_kernel_nofault(&dentry, dentry_ptr,
150 sizeof(struct dentry))) {
151 pr_warn("mapping->aops:%ps with invalid mapping->host->i_dentry.first %px\n",
152 a_ops, dentry_ptr);
153 } else {
154 /*
155 * if dentry is corrupted, the %pd handler may still
156 * crash, but it's unlikely that we reach here with a
157 * corrupted struct page
158 */
159 pr_warn("mapping->aops:%ps dentry name:\"%pd\"\n",
160 a_ops, &dentry);
161 }
162 }
163out_mapping:
164 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
165
166 pr_warn("%sflags: %#lx(%pGp)%s\n", type, page->flags, &page->flags,
167 page_cma ? " CMA" : "");
168
169hex_only:
170 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
171 sizeof(unsigned long), page,
172 sizeof(struct page), false);
173 if (head != page)
174 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
175 sizeof(unsigned long), head,
176 sizeof(struct page), false);
177
178 if (reason)
179 pr_warn("page dumped because: %s\n", reason);
180
181#ifdef CONFIG_MEMCG
182 if (!page_poisoned && page->mem_cgroup)
183 pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
184#endif
185}
186
187void dump_page(struct page *page, const char *reason)
188{
189 __dump_page(page, reason);
190 dump_page_owner(page);
191}
192EXPORT_SYMBOL(dump_page);
193
194#ifdef CONFIG_DEBUG_VM
195
196void dump_vma(const struct vm_area_struct *vma)
197{
198 pr_emerg("vma %px start %px end %px\n"
199 "next %px prev %px mm %px\n"
200 "prot %lx anon_vma %px vm_ops %px\n"
201 "pgoff %lx file %px private_data %px\n"
202 "flags: %#lx(%pGv)\n",
203 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
204 vma->vm_prev, vma->vm_mm,
205 (unsigned long)pgprot_val(vma->vm_page_prot),
206 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
207 vma->vm_file, vma->vm_private_data,
208 vma->vm_flags, &vma->vm_flags);
209}
210EXPORT_SYMBOL(dump_vma);
211
212void dump_mm(const struct mm_struct *mm)
213{
214 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
215#ifdef CONFIG_MMU
216 "get_unmapped_area %px\n"
217#endif
218 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
219 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
220 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
221 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
222 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
223 "start_brk %lx brk %lx start_stack %lx\n"
224 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
225 "binfmt %px flags %lx core_state %px\n"
226#ifdef CONFIG_AIO
227 "ioctx_table %px\n"
228#endif
229#ifdef CONFIG_MEMCG
230 "owner %px "
231#endif
232 "exe_file %px\n"
233#ifdef CONFIG_MMU_NOTIFIER
234 "notifier_subscriptions %px\n"
235#endif
236#ifdef CONFIG_NUMA_BALANCING
237 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
238#endif
239 "tlb_flush_pending %d\n"
240 "def_flags: %#lx(%pGv)\n",
241
242 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
243#ifdef CONFIG_MMU
244 mm->get_unmapped_area,
245#endif
246 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
247 mm->pgd, atomic_read(&mm->mm_users),
248 atomic_read(&mm->mm_count),
249 mm_pgtables_bytes(mm),
250 mm->map_count,
251 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
252 (u64)atomic64_read(&mm->pinned_vm),
253 mm->data_vm, mm->exec_vm, mm->stack_vm,
254 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
255 mm->start_brk, mm->brk, mm->start_stack,
256 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
257 mm->binfmt, mm->flags, mm->core_state,
258#ifdef CONFIG_AIO
259 mm->ioctx_table,
260#endif
261#ifdef CONFIG_MEMCG
262 mm->owner,
263#endif
264 mm->exe_file,
265#ifdef CONFIG_MMU_NOTIFIER
266 mm->notifier_subscriptions,
267#endif
268#ifdef CONFIG_NUMA_BALANCING
269 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
270#endif
271 atomic_read(&mm->tlb_flush_pending),
272 mm->def_flags, &mm->def_flags
273 );
274}
275
276static bool page_init_poisoning __read_mostly = true;
277
278static int __init setup_vm_debug(char *str)
279{
280 bool __page_init_poisoning = true;
281
282 /*
283 * Calling vm_debug with no arguments is equivalent to requesting
284 * to enable all debugging options we can control.
285 */
286 if (*str++ != '=' || !*str)
287 goto out;
288
289 __page_init_poisoning = false;
290 if (*str == '-')
291 goto out;
292
293 while (*str) {
294 switch (tolower(*str)) {
295 case'p':
296 __page_init_poisoning = true;
297 break;
298 default:
299 pr_err("vm_debug option '%c' unknown. skipped\n",
300 *str);
301 }
302
303 str++;
304 }
305out:
306 if (page_init_poisoning && !__page_init_poisoning)
307 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
308
309 page_init_poisoning = __page_init_poisoning;
310
311 return 1;
312}
313__setup("vm_debug", setup_vm_debug);
314
315void page_init_poison(struct page *page, size_t size)
316{
317 if (page_init_poisoning)
318 memset(page, PAGE_POISON_PATTERN, size);
319}
320EXPORT_SYMBOL_GPL(page_init_poison);
321#endif /* CONFIG_DEBUG_VM */