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 pagetype_names[] = {
40 : __def_pagetype_names,
41 : {0, NULL}
42 : };
43 :
44 : const struct trace_print_flags gfpflag_names[] = {
45 : __def_gfpflag_names,
46 : {0, NULL}
47 : };
48 :
49 : const struct trace_print_flags vmaflag_names[] = {
50 : __def_vmaflag_names,
51 : {0, NULL}
52 : };
53 :
54 0 : static void __dump_page(struct page *page)
55 : {
56 0 : struct folio *folio = page_folio(page);
57 0 : struct page *head = &folio->page;
58 : struct address_space *mapping;
59 0 : bool compound = PageCompound(page);
60 : /*
61 : * Accessing the pageblock without the zone lock. It could change to
62 : * "isolate" again in the meantime, but since we are just dumping the
63 : * state for debugging, it should be fine to accept a bit of
64 : * inaccuracy here due to racing.
65 : */
66 0 : bool page_cma = is_migrate_cma_page(page);
67 : int mapcount;
68 0 : char *type = "";
69 :
70 0 : if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
71 : /*
72 : * Corrupt page, so we cannot call page_mapping. Instead, do a
73 : * safe subset of the steps that page_mapping() does. Caution:
74 : * this will be misleading for tail pages, PageSwapCache pages,
75 : * and potentially other situations. (See the page_mapping()
76 : * implementation for what's missing here.)
77 : */
78 0 : unsigned long tmp = (unsigned long)page->mapping;
79 :
80 0 : if (tmp & PAGE_MAPPING_ANON)
81 : mapping = NULL;
82 : else
83 0 : mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
84 : head = page;
85 : folio = (struct folio *)page;
86 : compound = false;
87 : } else {
88 0 : mapping = page_mapping(page);
89 : }
90 :
91 : /*
92 : * Avoid VM_BUG_ON() in page_mapcount().
93 : * page->_mapcount space in struct page is used by sl[aou]b pages to
94 : * encode own info.
95 : */
96 0 : mapcount = PageSlab(head) ? 0 : page_mapcount(page);
97 :
98 0 : pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
99 : page, page_ref_count(head), mapcount, mapping,
100 : page_to_pgoff(page), page_to_pfn(page));
101 0 : if (compound) {
102 0 : pr_warn("head:%p order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
103 : head, compound_order(head),
104 : folio_entire_mapcount(folio),
105 : folio_nr_pages_mapped(folio),
106 : atomic_read(&folio->_pincount));
107 : }
108 :
109 : #ifdef CONFIG_MEMCG
110 : if (head->memcg_data)
111 : pr_warn("memcg:%lx\n", head->memcg_data);
112 : #endif
113 0 : if (PageKsm(page))
114 : type = "ksm ";
115 0 : else if (PageAnon(page))
116 : type = "anon ";
117 0 : else if (mapping)
118 0 : dump_mapping(mapping);
119 : BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
120 :
121 0 : pr_warn("%sflags: %pGp%s\n", type, &head->flags,
122 : page_cma ? " CMA" : "");
123 0 : pr_warn("page_type: %pGt\n", &head->page_type);
124 :
125 0 : print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
126 : sizeof(unsigned long), page,
127 : sizeof(struct page), false);
128 0 : if (head != page)
129 0 : print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
130 : sizeof(unsigned long), head,
131 : sizeof(struct page), false);
132 0 : }
133 :
134 0 : void dump_page(struct page *page, const char *reason)
135 : {
136 0 : if (PagePoisoned(page))
137 0 : pr_warn("page:%p is uninitialized and poisoned", page);
138 : else
139 0 : __dump_page(page);
140 0 : if (reason)
141 0 : pr_warn("page dumped because: %s\n", reason);
142 0 : dump_page_owner(page);
143 0 : }
144 : EXPORT_SYMBOL(dump_page);
145 :
146 : #ifdef CONFIG_DEBUG_VM
147 :
148 : void dump_vma(const struct vm_area_struct *vma)
149 : {
150 : pr_emerg("vma %px start %px end %px mm %px\n"
151 : "prot %lx anon_vma %px vm_ops %px\n"
152 : "pgoff %lx file %px private_data %px\n"
153 : "flags: %#lx(%pGv)\n",
154 : vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
155 : (unsigned long)pgprot_val(vma->vm_page_prot),
156 : vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
157 : vma->vm_file, vma->vm_private_data,
158 : vma->vm_flags, &vma->vm_flags);
159 : }
160 : EXPORT_SYMBOL(dump_vma);
161 :
162 : void dump_mm(const struct mm_struct *mm)
163 : {
164 : pr_emerg("mm %px task_size %lu\n"
165 : #ifdef CONFIG_MMU
166 : "get_unmapped_area %px\n"
167 : #endif
168 : "mmap_base %lu mmap_legacy_base %lu\n"
169 : "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
170 : "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
171 : "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
172 : "start_code %lx end_code %lx start_data %lx end_data %lx\n"
173 : "start_brk %lx brk %lx start_stack %lx\n"
174 : "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
175 : "binfmt %px flags %lx\n"
176 : #ifdef CONFIG_AIO
177 : "ioctx_table %px\n"
178 : #endif
179 : #ifdef CONFIG_MEMCG
180 : "owner %px "
181 : #endif
182 : "exe_file %px\n"
183 : #ifdef CONFIG_MMU_NOTIFIER
184 : "notifier_subscriptions %px\n"
185 : #endif
186 : #ifdef CONFIG_NUMA_BALANCING
187 : "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
188 : #endif
189 : "tlb_flush_pending %d\n"
190 : "def_flags: %#lx(%pGv)\n",
191 :
192 : mm, mm->task_size,
193 : #ifdef CONFIG_MMU
194 : mm->get_unmapped_area,
195 : #endif
196 : mm->mmap_base, mm->mmap_legacy_base,
197 : mm->pgd, atomic_read(&mm->mm_users),
198 : atomic_read(&mm->mm_count),
199 : mm_pgtables_bytes(mm),
200 : mm->map_count,
201 : mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
202 : (u64)atomic64_read(&mm->pinned_vm),
203 : mm->data_vm, mm->exec_vm, mm->stack_vm,
204 : mm->start_code, mm->end_code, mm->start_data, mm->end_data,
205 : mm->start_brk, mm->brk, mm->start_stack,
206 : mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
207 : mm->binfmt, mm->flags,
208 : #ifdef CONFIG_AIO
209 : mm->ioctx_table,
210 : #endif
211 : #ifdef CONFIG_MEMCG
212 : mm->owner,
213 : #endif
214 : mm->exe_file,
215 : #ifdef CONFIG_MMU_NOTIFIER
216 : mm->notifier_subscriptions,
217 : #endif
218 : #ifdef CONFIG_NUMA_BALANCING
219 : mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
220 : #endif
221 : atomic_read(&mm->tlb_flush_pending),
222 : mm->def_flags, &mm->def_flags
223 : );
224 : }
225 : EXPORT_SYMBOL(dump_mm);
226 :
227 : static bool page_init_poisoning __read_mostly = true;
228 :
229 : static int __init setup_vm_debug(char *str)
230 : {
231 : bool __page_init_poisoning = true;
232 :
233 : /*
234 : * Calling vm_debug with no arguments is equivalent to requesting
235 : * to enable all debugging options we can control.
236 : */
237 : if (*str++ != '=' || !*str)
238 : goto out;
239 :
240 : __page_init_poisoning = false;
241 : if (*str == '-')
242 : goto out;
243 :
244 : while (*str) {
245 : switch (tolower(*str)) {
246 : case'p':
247 : __page_init_poisoning = true;
248 : break;
249 : default:
250 : pr_err("vm_debug option '%c' unknown. skipped\n",
251 : *str);
252 : }
253 :
254 : str++;
255 : }
256 : out:
257 : if (page_init_poisoning && !__page_init_poisoning)
258 : pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
259 :
260 : page_init_poisoning = __page_init_poisoning;
261 :
262 : return 1;
263 : }
264 : __setup("vm_debug", setup_vm_debug);
265 :
266 : void page_init_poison(struct page *page, size_t size)
267 : {
268 : if (page_init_poisoning)
269 : memset(page, PAGE_POISON_PATTERN, size);
270 : }
271 : #endif /* CONFIG_DEBUG_VM */
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