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
30 const char *migrate_reason_names[MR_TYPES] = {
31 MIGRATE_REASON
32 };
33
34 const struct trace_print_flags pageflag_names[] = {
35 __def_pageflag_names,
36 {0, NULL}
37 };
38
39 const struct trace_print_flags gfpflag_names[] = {
40 __def_gfpflag_names,
41 {0, NULL}
42 };
43
44 const struct trace_print_flags vmaflag_names[] = {
45 __def_vmaflag_names,
46 {0, NULL}
47 };
48
49 #define DEF_PAGETYPE_NAME(_name) [PGTY_##_name - 0xf0] = __stringify(_name)
50
51 static const char *page_type_names[] = {
52 DEF_PAGETYPE_NAME(slab),
53 DEF_PAGETYPE_NAME(hugetlb),
54 DEF_PAGETYPE_NAME(offline),
55 DEF_PAGETYPE_NAME(guard),
56 DEF_PAGETYPE_NAME(table),
57 DEF_PAGETYPE_NAME(buddy),
58 DEF_PAGETYPE_NAME(unaccepted),
59 };
60
page_type_name(unsigned int page_type)61 static const char *page_type_name(unsigned int page_type)
62 {
63 unsigned i = (page_type >> 24) - 0xf0;
64
65 if (i >= ARRAY_SIZE(page_type_names))
66 return "unknown";
67 return page_type_names[i];
68 }
69
__dump_folio(struct folio * folio,struct page * page,unsigned long pfn,unsigned long idx)70 static void __dump_folio(struct folio *folio, struct page *page,
71 unsigned long pfn, unsigned long idx)
72 {
73 struct address_space *mapping = folio_mapping(folio);
74 int mapcount = atomic_read(&page->_mapcount);
75 char *type = "";
76
77 mapcount = page_mapcount_is_type(mapcount) ? 0 : mapcount + 1;
78 pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
79 folio_ref_count(folio), mapcount, mapping,
80 folio->index + idx, pfn);
81 if (folio_test_large(folio)) {
82 int pincount = 0;
83
84 if (folio_has_pincount(folio))
85 pincount = atomic_read(&folio->_pincount);
86
87 pr_warn("head: order:%u mapcount:%d entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
88 folio_order(folio),
89 folio_mapcount(folio),
90 folio_entire_mapcount(folio),
91 folio_nr_pages_mapped(folio),
92 pincount);
93 }
94
95 #ifdef CONFIG_MEMCG
96 if (folio->memcg_data)
97 pr_warn("memcg:%lx\n", folio->memcg_data);
98 #endif
99 if (folio_test_ksm(folio))
100 type = "ksm ";
101 else if (folio_test_anon(folio))
102 type = "anon ";
103 else if (mapping)
104 dump_mapping(mapping);
105 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
106
107 /*
108 * Accessing the pageblock without the zone lock. It could change to
109 * "isolate" again in the meantime, but since we are just dumping the
110 * state for debugging, it should be fine to accept a bit of
111 * inaccuracy here due to racing.
112 */
113 pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
114 is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
115 if (page_has_type(&folio->page))
116 pr_warn("page_type: %x(%s)\n", folio->page.page_type >> 24,
117 page_type_name(folio->page.page_type));
118
119 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
120 sizeof(unsigned long), page,
121 sizeof(struct page), false);
122 if (folio_test_large(folio))
123 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
124 sizeof(unsigned long), folio,
125 2 * sizeof(struct page), false);
126 }
127
__dump_page(const struct page * page)128 static void __dump_page(const struct page *page)
129 {
130 struct folio *foliop, folio;
131 struct page precise;
132 unsigned long head;
133 unsigned long pfn = page_to_pfn(page);
134 unsigned long idx, nr_pages = 1;
135 int loops = 5;
136
137 again:
138 memcpy(&precise, page, sizeof(*page));
139 head = precise.compound_head;
140 if ((head & 1) == 0) {
141 foliop = (struct folio *)&precise;
142 idx = 0;
143 if (!folio_test_large(foliop))
144 goto dump;
145 foliop = (struct folio *)page;
146 } else {
147 foliop = (struct folio *)(head - 1);
148 idx = folio_page_idx(foliop, page);
149 }
150
151 if (idx < MAX_FOLIO_NR_PAGES) {
152 memcpy(&folio, foliop, 2 * sizeof(struct page));
153 nr_pages = folio_nr_pages(&folio);
154 if (nr_pages > 1)
155 memcpy(&folio.__page_2, &foliop->__page_2,
156 sizeof(struct page));
157 foliop = &folio;
158 }
159
160 if (idx > nr_pages) {
161 if (loops-- > 0)
162 goto again;
163 pr_warn("page does not match folio\n");
164 precise.compound_head &= ~1UL;
165 foliop = (struct folio *)&precise;
166 idx = 0;
167 }
168
169 dump:
170 __dump_folio(foliop, &precise, pfn, idx);
171 }
172
dump_page(const struct page * page,const char * reason)173 void dump_page(const struct page *page, const char *reason)
174 {
175 if (PagePoisoned(page))
176 pr_warn("page:%p is uninitialized and poisoned\n", page);
177 else
178 __dump_page(page);
179 if (reason)
180 pr_warn("page dumped because: %s\n", reason);
181 dump_page_owner(page);
182 }
183 EXPORT_SYMBOL(dump_page);
184
185 #ifdef CONFIG_DEBUG_VM
186
dump_vma(const struct vm_area_struct * vma)187 void dump_vma(const struct vm_area_struct *vma)
188 {
189 pr_emerg("vma %px start %px end %px mm %px\n"
190 "prot %lx anon_vma %px vm_ops %px\n"
191 "pgoff %lx file %px private_data %px\n"
192 #ifdef CONFIG_PER_VMA_LOCK
193 "refcnt %x\n"
194 #endif
195 "flags: %#lx(%pGv)\n",
196 vma, (void *)vma->vm_start, (void *)vma->vm_end, 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 #ifdef CONFIG_PER_VMA_LOCK
201 refcount_read(&vma->vm_refcnt),
202 #endif
203 vma->vm_flags, &vma->vm_flags);
204 }
205 EXPORT_SYMBOL(dump_vma);
206
dump_mm(const struct mm_struct * mm)207 void dump_mm(const struct mm_struct *mm)
208 {
209 pr_emerg("mm %px task_size %lu\n"
210 "mmap_base %lu mmap_legacy_base %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\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->task_size,
235 mm->mmap_base, mm->mmap_legacy_base,
236 mm->pgd, atomic_read(&mm->mm_users),
237 atomic_read(&mm->mm_count),
238 mm_pgtables_bytes(mm),
239 mm->map_count,
240 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
241 (u64)atomic64_read(&mm->pinned_vm),
242 mm->data_vm, mm->exec_vm, mm->stack_vm,
243 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
244 mm->start_brk, mm->brk, mm->start_stack,
245 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
246 mm->binfmt, mm->flags,
247 #ifdef CONFIG_AIO
248 mm->ioctx_table,
249 #endif
250 #ifdef CONFIG_MEMCG
251 mm->owner,
252 #endif
253 mm->exe_file,
254 #ifdef CONFIG_MMU_NOTIFIER
255 mm->notifier_subscriptions,
256 #endif
257 #ifdef CONFIG_NUMA_BALANCING
258 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
259 #endif
260 atomic_read(&mm->tlb_flush_pending),
261 mm->def_flags, &mm->def_flags
262 );
263 }
264 EXPORT_SYMBOL(dump_mm);
265
dump_vmg(const struct vma_merge_struct * vmg,const char * reason)266 void dump_vmg(const struct vma_merge_struct *vmg, const char *reason)
267 {
268 if (reason)
269 pr_warn("vmg %px dumped because: %s\n", vmg, reason);
270
271 if (!vmg) {
272 pr_warn("vmg %px state: (NULL)\n", vmg);
273 return;
274 }
275
276 pr_warn("vmg %px state: mm %px pgoff %lx\n"
277 "vmi %px [%lx,%lx)\n"
278 "prev %px middle %px next %px target %px\n"
279 "start %lx end %lx flags %lx\n"
280 "file %px anon_vma %px policy %px\n"
281 "uffd_ctx %px\n"
282 "anon_name %px\n"
283 "state %x\n"
284 "just_expand %d\n"
285 "__adjust_middle_start %d __adjust_next_start %d\n"
286 "__remove_middle %d __remove_next %d\n",
287 vmg, vmg->mm, vmg->pgoff,
288 vmg->vmi, vmg->vmi ? vma_iter_addr(vmg->vmi) : 0,
289 vmg->vmi ? vma_iter_end(vmg->vmi) : 0,
290 vmg->prev, vmg->middle, vmg->next, vmg->target,
291 vmg->start, vmg->end, vmg->flags,
292 vmg->file, vmg->anon_vma, vmg->policy,
293 #ifdef CONFIG_USERFAULTFD
294 vmg->uffd_ctx.ctx,
295 #else
296 (void *)0,
297 #endif
298 vmg->anon_name,
299 (int)vmg->state,
300 vmg->just_expand,
301 vmg->__adjust_middle_start, vmg->__adjust_next_start,
302 vmg->__remove_middle, vmg->__remove_next);
303
304 if (vmg->mm) {
305 pr_warn("vmg %px mm:\n", vmg);
306 dump_mm(vmg->mm);
307 } else {
308 pr_warn("vmg %px mm: (NULL)\n", vmg);
309 }
310
311 if (vmg->prev) {
312 pr_warn("vmg %px prev:\n", vmg);
313 dump_vma(vmg->prev);
314 } else {
315 pr_warn("vmg %px prev: (NULL)\n", vmg);
316 }
317
318 if (vmg->middle) {
319 pr_warn("vmg %px middle:\n", vmg);
320 dump_vma(vmg->middle);
321 } else {
322 pr_warn("vmg %px middle: (NULL)\n", vmg);
323 }
324
325 if (vmg->next) {
326 pr_warn("vmg %px next:\n", vmg);
327 dump_vma(vmg->next);
328 } else {
329 pr_warn("vmg %px next: (NULL)\n", vmg);
330 }
331
332 #ifdef CONFIG_DEBUG_VM_MAPLE_TREE
333 if (vmg->vmi) {
334 pr_warn("vmg %px vmi:\n", vmg);
335 vma_iter_dump_tree(vmg->vmi);
336 } else {
337 pr_warn("vmg %px vmi: (NULL)\n", vmg);
338 }
339 #endif
340 }
341 EXPORT_SYMBOL(dump_vmg);
342
343 static bool page_init_poisoning __read_mostly = true;
344
setup_vm_debug(char * str)345 static int __init setup_vm_debug(char *str)
346 {
347 bool __page_init_poisoning = true;
348
349 /*
350 * Calling vm_debug with no arguments is equivalent to requesting
351 * to enable all debugging options we can control.
352 */
353 if (*str++ != '=' || !*str)
354 goto out;
355
356 __page_init_poisoning = false;
357 if (*str == '-')
358 goto out;
359
360 while (*str) {
361 switch (tolower(*str)) {
362 case'p':
363 __page_init_poisoning = true;
364 break;
365 default:
366 pr_err("vm_debug option '%c' unknown. skipped\n",
367 *str);
368 }
369
370 str++;
371 }
372 out:
373 if (page_init_poisoning && !__page_init_poisoning)
374 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
375
376 page_init_poisoning = __page_init_poisoning;
377
378 return 1;
379 }
380 __setup("vm_debug", setup_vm_debug);
381
page_init_poison(struct page * page,size_t size)382 void page_init_poison(struct page *page, size_t size)
383 {
384 if (page_init_poisoning)
385 memset(page, PAGE_POISON_PATTERN, size);
386 }
387
vma_iter_dump_tree(const struct vma_iterator * vmi)388 void vma_iter_dump_tree(const struct vma_iterator *vmi)
389 {
390 #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
391 mas_dump(&vmi->mas);
392 mt_dump(vmi->mas.tree, mt_dump_hex);
393 #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
394 }
395
396 #endif /* CONFIG_DEBUG_VM */
397