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) + 1;
75 char *type = "";
76
77 if (page_mapcount_is_type(mapcount))
78 mapcount = 0;
79
80 pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
81 folio_ref_count(folio), mapcount, mapping,
82 folio->index + idx, pfn);
83 if (folio_test_large(folio)) {
84 int pincount = 0;
85
86 if (folio_has_pincount(folio))
87 pincount = atomic_read(&folio->_pincount);
88
89 pr_warn("head: order:%u mapcount:%d entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
90 folio_order(folio),
91 folio_mapcount(folio),
92 folio_entire_mapcount(folio),
93 folio_nr_pages_mapped(folio),
94 pincount);
95 }
96
97 #ifdef CONFIG_MEMCG
98 if (folio->memcg_data)
99 pr_warn("memcg:%lx\n", folio->memcg_data);
100 #endif
101 if (folio_test_ksm(folio))
102 type = "ksm ";
103 else if (folio_test_anon(folio))
104 type = "anon ";
105 else if (mapping)
106 dump_mapping(mapping);
107 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
108
109 /*
110 * Accessing the pageblock without the zone lock. It could change to
111 * "isolate" again in the meantime, but since we are just dumping the
112 * state for debugging, it should be fine to accept a bit of
113 * inaccuracy here due to racing.
114 */
115 pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
116 is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
117 if (page_has_type(&folio->page))
118 pr_warn("page_type: %x(%s)\n", folio->page.page_type >> 24,
119 page_type_name(folio->page.page_type));
120
121 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
122 sizeof(unsigned long), page,
123 sizeof(struct page), false);
124 if (folio_test_large(folio))
125 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
126 sizeof(unsigned long), folio,
127 2 * sizeof(struct page), false);
128 }
129
__dump_page(const struct page * page)130 static void __dump_page(const struct page *page)
131 {
132 struct folio *foliop, folio;
133 struct page precise;
134 unsigned long head;
135 unsigned long pfn = page_to_pfn(page);
136 unsigned long idx, nr_pages = 1;
137 int loops = 5;
138
139 again:
140 memcpy(&precise, page, sizeof(*page));
141 head = precise.compound_head;
142 if ((head & 1) == 0) {
143 foliop = (struct folio *)&precise;
144 idx = 0;
145 if (!folio_test_large(foliop))
146 goto dump;
147 foliop = (struct folio *)page;
148 } else {
149 foliop = (struct folio *)(head - 1);
150 idx = folio_page_idx(foliop, page);
151 }
152
153 if (idx < MAX_FOLIO_NR_PAGES) {
154 memcpy(&folio, foliop, 2 * sizeof(struct page));
155 nr_pages = folio_nr_pages(&folio);
156 if (nr_pages > 1)
157 memcpy(&folio.__page_2, &foliop->__page_2,
158 sizeof(struct page));
159 foliop = &folio;
160 }
161
162 if (idx > nr_pages) {
163 if (loops-- > 0)
164 goto again;
165 pr_warn("page does not match folio\n");
166 precise.compound_head &= ~1UL;
167 foliop = (struct folio *)&precise;
168 idx = 0;
169 }
170
171 dump:
172 __dump_folio(foliop, &precise, pfn, idx);
173 }
174
dump_page(const struct page * page,const char * reason)175 void dump_page(const struct page *page, const char *reason)
176 {
177 if (PagePoisoned(page))
178 pr_warn("page:%p is uninitialized and poisoned\n", page);
179 else
180 __dump_page(page);
181 if (reason)
182 pr_warn("page dumped because: %s\n", reason);
183 dump_page_owner(page);
184 }
185 EXPORT_SYMBOL(dump_page);
186
187 #ifdef CONFIG_DEBUG_VM
188
dump_vma(const struct vm_area_struct * vma)189 void dump_vma(const struct vm_area_struct *vma)
190 {
191 pr_emerg("vma %px start %px end %px mm %px\n"
192 "prot %lx anon_vma %px vm_ops %px\n"
193 "pgoff %lx file %px private_data %px\n"
194 #ifdef CONFIG_PER_VMA_LOCK
195 "refcnt %x\n"
196 #endif
197 "flags: %#lx(%pGv)\n",
198 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
199 (unsigned long)pgprot_val(vma->vm_page_prot),
200 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
201 vma->vm_file, vma->vm_private_data,
202 #ifdef CONFIG_PER_VMA_LOCK
203 refcount_read(&vma->vm_refcnt),
204 #endif
205 vma->vm_flags, &vma->vm_flags);
206 }
207 EXPORT_SYMBOL(dump_vma);
208
dump_mm(const struct mm_struct * mm)209 void dump_mm(const struct mm_struct *mm)
210 {
211 pr_emerg("mm %px task_size %lu\n"
212 "mmap_base %lu mmap_legacy_base %lu\n"
213 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
214 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
215 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
216 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
217 "start_brk %lx brk %lx start_stack %lx\n"
218 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
219 "binfmt %px flags %lx\n"
220 #ifdef CONFIG_AIO
221 "ioctx_table %px\n"
222 #endif
223 #ifdef CONFIG_MEMCG
224 "owner %px "
225 #endif
226 "exe_file %px\n"
227 #ifdef CONFIG_MMU_NOTIFIER
228 "notifier_subscriptions %px\n"
229 #endif
230 #ifdef CONFIG_NUMA_BALANCING
231 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
232 #endif
233 "tlb_flush_pending %d\n"
234 "def_flags: %#lx(%pGv)\n",
235
236 mm, mm->task_size,
237 mm->mmap_base, mm->mmap_legacy_base,
238 mm->pgd, atomic_read(&mm->mm_users),
239 atomic_read(&mm->mm_count),
240 mm_pgtables_bytes(mm),
241 mm->map_count,
242 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
243 (u64)atomic64_read(&mm->pinned_vm),
244 mm->data_vm, mm->exec_vm, mm->stack_vm,
245 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
246 mm->start_brk, mm->brk, mm->start_stack,
247 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
248 mm->binfmt, mm->flags,
249 #ifdef CONFIG_AIO
250 mm->ioctx_table,
251 #endif
252 #ifdef CONFIG_MEMCG
253 mm->owner,
254 #endif
255 mm->exe_file,
256 #ifdef CONFIG_MMU_NOTIFIER
257 mm->notifier_subscriptions,
258 #endif
259 #ifdef CONFIG_NUMA_BALANCING
260 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
261 #endif
262 atomic_read(&mm->tlb_flush_pending),
263 mm->def_flags, &mm->def_flags
264 );
265 }
266 EXPORT_SYMBOL(dump_mm);
267
dump_vmg(const struct vma_merge_struct * vmg,const char * reason)268 void dump_vmg(const struct vma_merge_struct *vmg, const char *reason)
269 {
270 if (reason)
271 pr_warn("vmg %px dumped because: %s\n", vmg, reason);
272
273 if (!vmg) {
274 pr_warn("vmg %px state: (NULL)\n", vmg);
275 return;
276 }
277
278 pr_warn("vmg %px state: mm %px pgoff %lx\n"
279 "vmi %px [%lx,%lx)\n"
280 "prev %px middle %px next %px target %px\n"
281 "start %lx end %lx flags %lx\n"
282 "file %px anon_vma %px policy %px\n"
283 "uffd_ctx %px\n"
284 "anon_name %px\n"
285 "state %x\n"
286 "just_expand %d\n"
287 "__adjust_middle_start %d __adjust_next_start %d\n"
288 "__remove_middle %d __remove_next %d\n",
289 vmg, vmg->mm, vmg->pgoff,
290 vmg->vmi, vmg->vmi ? vma_iter_addr(vmg->vmi) : 0,
291 vmg->vmi ? vma_iter_end(vmg->vmi) : 0,
292 vmg->prev, vmg->middle, vmg->next, vmg->target,
293 vmg->start, vmg->end, vmg->flags,
294 vmg->file, vmg->anon_vma, vmg->policy,
295 #ifdef CONFIG_USERFAULTFD
296 vmg->uffd_ctx.ctx,
297 #else
298 (void *)0,
299 #endif
300 vmg->anon_name,
301 (int)vmg->state,
302 vmg->just_expand,
303 vmg->__adjust_middle_start, vmg->__adjust_next_start,
304 vmg->__remove_middle, vmg->__remove_next);
305
306 if (vmg->mm) {
307 pr_warn("vmg %px mm:\n", vmg);
308 dump_mm(vmg->mm);
309 } else {
310 pr_warn("vmg %px mm: (NULL)\n", vmg);
311 }
312
313 if (vmg->prev) {
314 pr_warn("vmg %px prev:\n", vmg);
315 dump_vma(vmg->prev);
316 } else {
317 pr_warn("vmg %px prev: (NULL)\n", vmg);
318 }
319
320 if (vmg->middle) {
321 pr_warn("vmg %px middle:\n", vmg);
322 dump_vma(vmg->middle);
323 } else {
324 pr_warn("vmg %px middle: (NULL)\n", vmg);
325 }
326
327 if (vmg->next) {
328 pr_warn("vmg %px next:\n", vmg);
329 dump_vma(vmg->next);
330 } else {
331 pr_warn("vmg %px next: (NULL)\n", vmg);
332 }
333
334 #ifdef CONFIG_DEBUG_VM_MAPLE_TREE
335 if (vmg->vmi) {
336 pr_warn("vmg %px vmi:\n", vmg);
337 vma_iter_dump_tree(vmg->vmi);
338 } else {
339 pr_warn("vmg %px vmi: (NULL)\n", vmg);
340 }
341 #endif
342 }
343 EXPORT_SYMBOL(dump_vmg);
344
345 static bool page_init_poisoning __read_mostly = true;
346
setup_vm_debug(char * str)347 static int __init setup_vm_debug(char *str)
348 {
349 bool __page_init_poisoning = true;
350
351 /*
352 * Calling vm_debug with no arguments is equivalent to requesting
353 * to enable all debugging options we can control.
354 */
355 if (*str++ != '=' || !*str)
356 goto out;
357
358 __page_init_poisoning = false;
359 if (*str == '-')
360 goto out;
361
362 while (*str) {
363 switch (tolower(*str)) {
364 case'p':
365 __page_init_poisoning = true;
366 break;
367 default:
368 pr_err("vm_debug option '%c' unknown. skipped\n",
369 *str);
370 }
371
372 str++;
373 }
374 out:
375 if (page_init_poisoning && !__page_init_poisoning)
376 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
377
378 page_init_poisoning = __page_init_poisoning;
379
380 return 1;
381 }
382 __setup("vm_debug", setup_vm_debug);
383
page_init_poison(struct page * page,size_t size)384 void page_init_poison(struct page *page, size_t size)
385 {
386 if (page_init_poisoning)
387 memset(page, PAGE_POISON_PATTERN, size);
388 }
389
vma_iter_dump_tree(const struct vma_iterator * vmi)390 void vma_iter_dump_tree(const struct vma_iterator *vmi)
391 {
392 #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
393 mas_dump(&vmi->mas);
394 mt_dump(vmi->mas.tree, mt_dump_hex);
395 #endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
396 }
397
398 #endif /* CONFIG_DEBUG_VM */
399