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