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