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
20 const char *migrate_reason_names[MR_TYPES] = {
21 "compaction",
22 "memory_failure",
23 "memory_hotplug",
24 "syscall_or_cpuset",
25 "mempolicy_mbind",
26 "numa_misplaced",
27 "cma",
28 };
29
30 const struct trace_print_flags pageflag_names[] = {
31 __def_pageflag_names,
32 {0, NULL}
33 };
34
35 const struct trace_print_flags gfpflag_names[] = {
36 __def_gfpflag_names,
37 {0, NULL}
38 };
39
40 const struct trace_print_flags vmaflag_names[] = {
41 __def_vmaflag_names,
42 {0, NULL}
43 };
44
__dump_page(struct page * page,const char * reason)45 void __dump_page(struct page *page, const char *reason)
46 {
47 struct address_space *mapping;
48 bool page_poisoned = PagePoisoned(page);
49 int mapcount;
50 char *type = "";
51
52 /*
53 * If struct page is poisoned don't access Page*() functions as that
54 * leads to recursive loop. Page*() check for poisoned pages, and calls
55 * dump_page() when detected.
56 */
57 if (page_poisoned) {
58 pr_warn("page:%px is uninitialized and poisoned", page);
59 goto hex_only;
60 }
61
62 mapping = page_mapping(page);
63
64 /*
65 * Avoid VM_BUG_ON() in page_mapcount().
66 * page->_mapcount space in struct page is used by sl[aou]b pages to
67 * encode own info.
68 */
69 mapcount = PageSlab(page) ? 0 : page_mapcount(page);
70
71 if (PageCompound(page))
72 pr_warn("page:%px refcount:%d mapcount:%d mapping:%px "
73 "index:%#lx compound_mapcount: %d\n",
74 page, page_ref_count(page), mapcount,
75 page->mapping, page_to_pgoff(page),
76 compound_mapcount(page));
77 else
78 pr_warn("page:%px refcount:%d mapcount:%d mapping:%px index:%#lx\n",
79 page, page_ref_count(page), mapcount,
80 page->mapping, page_to_pgoff(page));
81 if (PageKsm(page))
82 type = "ksm ";
83 else if (PageAnon(page))
84 type = "anon ";
85 else if (mapping) {
86 if (mapping->host && mapping->host->i_dentry.first) {
87 struct dentry *dentry;
88 dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
89 pr_warn("%ps name:\"%pd\"\n", mapping->a_ops, dentry);
90 } else
91 pr_warn("%ps\n", mapping->a_ops);
92 }
93 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
94
95 pr_warn("%sflags: %#lx(%pGp)\n", type, page->flags, &page->flags);
96
97 hex_only:
98 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
99 sizeof(unsigned long), page,
100 sizeof(struct page), false);
101
102 if (reason)
103 pr_warn("page dumped because: %s\n", reason);
104
105 #ifdef CONFIG_MEMCG
106 if (!page_poisoned && page->mem_cgroup)
107 pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
108 #endif
109 }
110
dump_page(struct page * page,const char * reason)111 void dump_page(struct page *page, const char *reason)
112 {
113 __dump_page(page, reason);
114 dump_page_owner(page);
115 }
116 EXPORT_SYMBOL(dump_page);
117
118 #ifdef CONFIG_DEBUG_VM
119
dump_vma(const struct vm_area_struct * vma)120 void dump_vma(const struct vm_area_struct *vma)
121 {
122 pr_emerg("vma %px start %px end %px\n"
123 "next %px prev %px mm %px\n"
124 "prot %lx anon_vma %px vm_ops %px\n"
125 "pgoff %lx file %px private_data %px\n"
126 "flags: %#lx(%pGv)\n",
127 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
128 vma->vm_prev, vma->vm_mm,
129 (unsigned long)pgprot_val(vma->vm_page_prot),
130 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
131 vma->vm_file, vma->vm_private_data,
132 vma->vm_flags, &vma->vm_flags);
133 }
134 EXPORT_SYMBOL(dump_vma);
135
dump_mm(const struct mm_struct * mm)136 void dump_mm(const struct mm_struct *mm)
137 {
138 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
139 #ifdef CONFIG_MMU
140 "get_unmapped_area %px\n"
141 #endif
142 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
143 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
144 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
145 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
146 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
147 "start_brk %lx brk %lx start_stack %lx\n"
148 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
149 "binfmt %px flags %lx core_state %px\n"
150 #ifdef CONFIG_AIO
151 "ioctx_table %px\n"
152 #endif
153 #ifdef CONFIG_MEMCG
154 "owner %px "
155 #endif
156 "exe_file %px\n"
157 #ifdef CONFIG_MMU_NOTIFIER
158 "mmu_notifier_mm %px\n"
159 #endif
160 #ifdef CONFIG_NUMA_BALANCING
161 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
162 #endif
163 "tlb_flush_pending %d\n"
164 "def_flags: %#lx(%pGv)\n",
165
166 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
167 #ifdef CONFIG_MMU
168 mm->get_unmapped_area,
169 #endif
170 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
171 mm->pgd, atomic_read(&mm->mm_users),
172 atomic_read(&mm->mm_count),
173 mm_pgtables_bytes(mm),
174 mm->map_count,
175 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
176 (u64)atomic64_read(&mm->pinned_vm),
177 mm->data_vm, mm->exec_vm, mm->stack_vm,
178 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
179 mm->start_brk, mm->brk, mm->start_stack,
180 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
181 mm->binfmt, mm->flags, mm->core_state,
182 #ifdef CONFIG_AIO
183 mm->ioctx_table,
184 #endif
185 #ifdef CONFIG_MEMCG
186 mm->owner,
187 #endif
188 mm->exe_file,
189 #ifdef CONFIG_MMU_NOTIFIER
190 mm->mmu_notifier_mm,
191 #endif
192 #ifdef CONFIG_NUMA_BALANCING
193 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
194 #endif
195 atomic_read(&mm->tlb_flush_pending),
196 mm->def_flags, &mm->def_flags
197 );
198 }
199
200 static bool page_init_poisoning __read_mostly = true;
201
setup_vm_debug(char * str)202 static int __init setup_vm_debug(char *str)
203 {
204 bool __page_init_poisoning = true;
205
206 /*
207 * Calling vm_debug with no arguments is equivalent to requesting
208 * to enable all debugging options we can control.
209 */
210 if (*str++ != '=' || !*str)
211 goto out;
212
213 __page_init_poisoning = false;
214 if (*str == '-')
215 goto out;
216
217 while (*str) {
218 switch (tolower(*str)) {
219 case'p':
220 __page_init_poisoning = true;
221 break;
222 default:
223 pr_err("vm_debug option '%c' unknown. skipped\n",
224 *str);
225 }
226
227 str++;
228 }
229 out:
230 if (page_init_poisoning && !__page_init_poisoning)
231 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
232
233 page_init_poisoning = __page_init_poisoning;
234
235 return 1;
236 }
237 __setup("vm_debug", setup_vm_debug);
238
page_init_poison(struct page * page,size_t size)239 void page_init_poison(struct page *page, size_t size)
240 {
241 if (page_init_poisoning)
242 memset(page, PAGE_POISON_PATTERN, size);
243 }
244 EXPORT_SYMBOL_GPL(page_init_poison);
245 #endif /* CONFIG_DEBUG_VM */
246