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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#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
30const char *migrate_reason_names[MR_TYPES] = {
31 MIGRATE_REASON
32};
33
34const struct trace_print_flags pageflag_names[] = {
35 __def_pageflag_names,
36 {0, NULL}
37};
38
39const struct trace_print_flags gfpflag_names[] = {
40 __def_gfpflag_names,
41 {0, NULL}
42};
43
44const 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
51static 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
61static 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
70static 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 pr_warn("head: order:%u mapcount:%d entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
83 folio_order(folio),
84 folio_mapcount(folio),
85 folio_entire_mapcount(folio),
86 folio_nr_pages_mapped(folio),
87 atomic_read(&folio->_pincount));
88 }
89
90#ifdef CONFIG_MEMCG
91 if (folio->memcg_data)
92 pr_warn("memcg:%lx\n", folio->memcg_data);
93#endif
94 if (folio_test_ksm(folio))
95 type = "ksm ";
96 else if (folio_test_anon(folio))
97 type = "anon ";
98 else if (mapping)
99 dump_mapping(mapping);
100 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
101
102 /*
103 * Accessing the pageblock without the zone lock. It could change to
104 * "isolate" again in the meantime, but since we are just dumping the
105 * state for debugging, it should be fine to accept a bit of
106 * inaccuracy here due to racing.
107 */
108 pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
109 is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
110 if (page_has_type(&folio->page))
111 pr_warn("page_type: %x(%s)\n", folio->page.page_type >> 24,
112 page_type_name(folio->page.page_type));
113
114 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
115 sizeof(unsigned long), page,
116 sizeof(struct page), false);
117 if (folio_test_large(folio))
118 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
119 sizeof(unsigned long), folio,
120 2 * sizeof(struct page), false);
121}
122
123static void __dump_page(const struct page *page)
124{
125 struct folio *foliop, folio;
126 struct page precise;
127 unsigned long head;
128 unsigned long pfn = page_to_pfn(page);
129 unsigned long idx, nr_pages = 1;
130 int loops = 5;
131
132again:
133 memcpy(&precise, page, sizeof(*page));
134 head = precise.compound_head;
135 if ((head & 1) == 0) {
136 foliop = (struct folio *)&precise;
137 idx = 0;
138 if (!folio_test_large(foliop))
139 goto dump;
140 foliop = (struct folio *)page;
141 } else {
142 foliop = (struct folio *)(head - 1);
143 idx = folio_page_idx(foliop, page);
144 }
145
146 if (idx < MAX_FOLIO_NR_PAGES) {
147 memcpy(&folio, foliop, 2 * sizeof(struct page));
148 nr_pages = folio_nr_pages(&folio);
149 foliop = &folio;
150 }
151
152 if (idx > nr_pages) {
153 if (loops-- > 0)
154 goto again;
155 pr_warn("page does not match folio\n");
156 precise.compound_head &= ~1UL;
157 foliop = (struct folio *)&precise;
158 idx = 0;
159 }
160
161dump:
162 __dump_folio(foliop, &precise, pfn, idx);
163}
164
165void dump_page(const struct page *page, const char *reason)
166{
167 if (PagePoisoned(page))
168 pr_warn("page:%p is uninitialized and poisoned", page);
169 else
170 __dump_page(page);
171 if (reason)
172 pr_warn("page dumped because: %s\n", reason);
173 dump_page_owner(page);
174}
175EXPORT_SYMBOL(dump_page);
176
177#ifdef CONFIG_DEBUG_VM
178
179void dump_vma(const struct vm_area_struct *vma)
180{
181 pr_emerg("vma %px start %px end %px mm %px\n"
182 "prot %lx anon_vma %px vm_ops %px\n"
183 "pgoff %lx file %px private_data %px\n"
184 "flags: %#lx(%pGv)\n",
185 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
186 (unsigned long)pgprot_val(vma->vm_page_prot),
187 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
188 vma->vm_file, vma->vm_private_data,
189 vma->vm_flags, &vma->vm_flags);
190}
191EXPORT_SYMBOL(dump_vma);
192
193void dump_mm(const struct mm_struct *mm)
194{
195 pr_emerg("mm %px task_size %lu\n"
196 "mmap_base %lu mmap_legacy_base %lu\n"
197 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
198 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
199 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
200 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
201 "start_brk %lx brk %lx start_stack %lx\n"
202 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
203 "binfmt %px flags %lx\n"
204#ifdef CONFIG_AIO
205 "ioctx_table %px\n"
206#endif
207#ifdef CONFIG_MEMCG
208 "owner %px "
209#endif
210 "exe_file %px\n"
211#ifdef CONFIG_MMU_NOTIFIER
212 "notifier_subscriptions %px\n"
213#endif
214#ifdef CONFIG_NUMA_BALANCING
215 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
216#endif
217 "tlb_flush_pending %d\n"
218 "def_flags: %#lx(%pGv)\n",
219
220 mm, mm->task_size,
221 mm->mmap_base, mm->mmap_legacy_base,
222 mm->pgd, atomic_read(&mm->mm_users),
223 atomic_read(&mm->mm_count),
224 mm_pgtables_bytes(mm),
225 mm->map_count,
226 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
227 (u64)atomic64_read(&mm->pinned_vm),
228 mm->data_vm, mm->exec_vm, mm->stack_vm,
229 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
230 mm->start_brk, mm->brk, mm->start_stack,
231 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
232 mm->binfmt, mm->flags,
233#ifdef CONFIG_AIO
234 mm->ioctx_table,
235#endif
236#ifdef CONFIG_MEMCG
237 mm->owner,
238#endif
239 mm->exe_file,
240#ifdef CONFIG_MMU_NOTIFIER
241 mm->notifier_subscriptions,
242#endif
243#ifdef CONFIG_NUMA_BALANCING
244 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
245#endif
246 atomic_read(&mm->tlb_flush_pending),
247 mm->def_flags, &mm->def_flags
248 );
249}
250EXPORT_SYMBOL(dump_mm);
251
252static bool page_init_poisoning __read_mostly = true;
253
254static int __init setup_vm_debug(char *str)
255{
256 bool __page_init_poisoning = true;
257
258 /*
259 * Calling vm_debug with no arguments is equivalent to requesting
260 * to enable all debugging options we can control.
261 */
262 if (*str++ != '=' || !*str)
263 goto out;
264
265 __page_init_poisoning = false;
266 if (*str == '-')
267 goto out;
268
269 while (*str) {
270 switch (tolower(*str)) {
271 case'p':
272 __page_init_poisoning = true;
273 break;
274 default:
275 pr_err("vm_debug option '%c' unknown. skipped\n",
276 *str);
277 }
278
279 str++;
280 }
281out:
282 if (page_init_poisoning && !__page_init_poisoning)
283 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
284
285 page_init_poisoning = __page_init_poisoning;
286
287 return 1;
288}
289__setup("vm_debug", setup_vm_debug);
290
291void page_init_poison(struct page *page, size_t size)
292{
293 if (page_init_poisoning)
294 memset(page, PAGE_POISON_PATTERN, size);
295}
296
297void vma_iter_dump_tree(const struct vma_iterator *vmi)
298{
299#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
300 mas_dump(&vmi->mas);
301 mt_dump(vmi->mas.tree, mt_dump_hex);
302#endif /* CONFIG_DEBUG_VM_MAPLE_TREE */
303}
304
305#endif /* CONFIG_DEBUG_VM */