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
20const 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
30const struct trace_print_flags pageflag_names[] = {
31 __def_pageflag_names,
32 {0, NULL}
33};
34
35const struct trace_print_flags gfpflag_names[] = {
36 __def_gfpflag_names,
37 {0, NULL}
38};
39
40const struct trace_print_flags vmaflag_names[] = {
41 __def_vmaflag_names,
42 {0, NULL}
43};
44
45void __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 pr_warn("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
71 page, page_ref_count(page), mapcount,
72 page->mapping, page_to_pgoff(page));
73 if (PageCompound(page))
74 pr_cont(" compound_mapcount: %d", compound_mapcount(page));
75 pr_cont("\n");
76 if (PageAnon(page))
77 pr_warn("anon ");
78 else if (PageKsm(page))
79 pr_warn("ksm ");
80 else if (mapping) {
81 pr_warn("%ps ", mapping->a_ops);
82 if (mapping->host->i_dentry.first) {
83 struct dentry *dentry;
84 dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
85 pr_warn("name:\"%pd\" ", dentry);
86 }
87 }
88 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
89
90 pr_warn("flags: %#lx(%pGp)\n", page->flags, &page->flags);
91
92hex_only:
93 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
94 sizeof(unsigned long), page,
95 sizeof(struct page), false);
96
97 if (reason)
98 pr_warn("page dumped because: %s\n", reason);
99
100#ifdef CONFIG_MEMCG
101 if (!page_poisoned && page->mem_cgroup)
102 pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
103#endif
104}
105
106void dump_page(struct page *page, const char *reason)
107{
108 __dump_page(page, reason);
109 dump_page_owner(page);
110}
111EXPORT_SYMBOL(dump_page);
112
113#ifdef CONFIG_DEBUG_VM
114
115void dump_vma(const struct vm_area_struct *vma)
116{
117 pr_emerg("vma %px start %px end %px\n"
118 "next %px prev %px mm %px\n"
119 "prot %lx anon_vma %px vm_ops %px\n"
120 "pgoff %lx file %px private_data %px\n"
121 "flags: %#lx(%pGv)\n",
122 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
123 vma->vm_prev, vma->vm_mm,
124 (unsigned long)pgprot_val(vma->vm_page_prot),
125 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
126 vma->vm_file, vma->vm_private_data,
127 vma->vm_flags, &vma->vm_flags);
128}
129EXPORT_SYMBOL(dump_vma);
130
131void dump_mm(const struct mm_struct *mm)
132{
133 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
134#ifdef CONFIG_MMU
135 "get_unmapped_area %px\n"
136#endif
137 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
138 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
139 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
140 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
141 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
142 "start_brk %lx brk %lx start_stack %lx\n"
143 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
144 "binfmt %px flags %lx core_state %px\n"
145#ifdef CONFIG_AIO
146 "ioctx_table %px\n"
147#endif
148#ifdef CONFIG_MEMCG
149 "owner %px "
150#endif
151 "exe_file %px\n"
152#ifdef CONFIG_MMU_NOTIFIER
153 "mmu_notifier_mm %px\n"
154#endif
155#ifdef CONFIG_NUMA_BALANCING
156 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
157#endif
158 "tlb_flush_pending %d\n"
159 "def_flags: %#lx(%pGv)\n",
160
161 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
162#ifdef CONFIG_MMU
163 mm->get_unmapped_area,
164#endif
165 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
166 mm->pgd, atomic_read(&mm->mm_users),
167 atomic_read(&mm->mm_count),
168 mm_pgtables_bytes(mm),
169 mm->map_count,
170 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
171 atomic64_read(&mm->pinned_vm),
172 mm->data_vm, mm->exec_vm, mm->stack_vm,
173 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
174 mm->start_brk, mm->brk, mm->start_stack,
175 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
176 mm->binfmt, mm->flags, mm->core_state,
177#ifdef CONFIG_AIO
178 mm->ioctx_table,
179#endif
180#ifdef CONFIG_MEMCG
181 mm->owner,
182#endif
183 mm->exe_file,
184#ifdef CONFIG_MMU_NOTIFIER
185 mm->mmu_notifier_mm,
186#endif
187#ifdef CONFIG_NUMA_BALANCING
188 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
189#endif
190 atomic_read(&mm->tlb_flush_pending),
191 mm->def_flags, &mm->def_flags
192 );
193}
194
195static bool page_init_poisoning __read_mostly = true;
196
197static int __init setup_vm_debug(char *str)
198{
199 bool __page_init_poisoning = true;
200
201 /*
202 * Calling vm_debug with no arguments is equivalent to requesting
203 * to enable all debugging options we can control.
204 */
205 if (*str++ != '=' || !*str)
206 goto out;
207
208 __page_init_poisoning = false;
209 if (*str == '-')
210 goto out;
211
212 while (*str) {
213 switch (tolower(*str)) {
214 case'p':
215 __page_init_poisoning = true;
216 break;
217 default:
218 pr_err("vm_debug option '%c' unknown. skipped\n",
219 *str);
220 }
221
222 str++;
223 }
224out:
225 if (page_init_poisoning && !__page_init_poisoning)
226 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
227
228 page_init_poisoning = __page_init_poisoning;
229
230 return 1;
231}
232__setup("vm_debug", setup_vm_debug);
233
234void page_init_poison(struct page *page, size_t size)
235{
236 if (page_init_poisoning)
237 memset(page, PAGE_POISON_PATTERN, size);
238}
239EXPORT_SYMBOL_GPL(page_init_poison);
240#endif /* CONFIG_DEBUG_VM */
241