xref: /openbmc/linux/mm/debug.c (revision 1cac4f26) 
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 
45 void __dump_page(struct page *page, const char *reason)
46 {
47 	struct address_space *mapping = page_mapping(page);
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 	/*
62 	 * Avoid VM_BUG_ON() in page_mapcount().
63 	 * page->_mapcount space in struct page is used by sl[aou]b pages to
64 	 * encode own info.
65 	 */
66 	mapcount = PageSlab(page) ? 0 : page_mapcount(page);
67 
68 	pr_warn("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
69 		  page, page_ref_count(page), mapcount,
70 		  page->mapping, page_to_pgoff(page));
71 	if (PageCompound(page))
72 		pr_cont(" compound_mapcount: %d", compound_mapcount(page));
73 	pr_cont("\n");
74 	if (PageAnon(page))
75 		pr_warn("anon ");
76 	else if (PageKsm(page))
77 		pr_warn("ksm ");
78 	else if (mapping) {
79 		pr_warn("%ps ", mapping->a_ops);
80 		if (mapping->host->i_dentry.first) {
81 			struct dentry *dentry;
82 			dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
83 			pr_warn("name:\"%pd\" ", dentry);
84 		}
85 	}
86 	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
87 
88 	pr_warn("flags: %#lx(%pGp)\n", page->flags, &page->flags);
89 
90 hex_only:
91 	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
92 			sizeof(unsigned long), page,
93 			sizeof(struct page), false);
94 
95 	if (reason)
96 		pr_warn("page dumped because: %s\n", reason);
97 
98 #ifdef CONFIG_MEMCG
99 	if (!page_poisoned && page->mem_cgroup)
100 		pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
101 #endif
102 }
103 
104 void dump_page(struct page *page, const char *reason)
105 {
106 	__dump_page(page, reason);
107 	dump_page_owner(page);
108 }
109 EXPORT_SYMBOL(dump_page);
110 
111 #ifdef CONFIG_DEBUG_VM
112 
113 void dump_vma(const struct vm_area_struct *vma)
114 {
115 	pr_emerg("vma %px start %px end %px\n"
116 		"next %px prev %px mm %px\n"
117 		"prot %lx anon_vma %px vm_ops %px\n"
118 		"pgoff %lx file %px private_data %px\n"
119 		"flags: %#lx(%pGv)\n",
120 		vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
121 		vma->vm_prev, vma->vm_mm,
122 		(unsigned long)pgprot_val(vma->vm_page_prot),
123 		vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
124 		vma->vm_file, vma->vm_private_data,
125 		vma->vm_flags, &vma->vm_flags);
126 }
127 EXPORT_SYMBOL(dump_vma);
128 
129 void dump_mm(const struct mm_struct *mm)
130 {
131 	pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
132 #ifdef CONFIG_MMU
133 		"get_unmapped_area %px\n"
134 #endif
135 		"mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
136 		"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
137 		"hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
138 		"pinned_vm %lx data_vm %lx exec_vm %lx stack_vm %lx\n"
139 		"start_code %lx end_code %lx start_data %lx end_data %lx\n"
140 		"start_brk %lx brk %lx start_stack %lx\n"
141 		"arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
142 		"binfmt %px flags %lx core_state %px\n"
143 #ifdef CONFIG_AIO
144 		"ioctx_table %px\n"
145 #endif
146 #ifdef CONFIG_MEMCG
147 		"owner %px "
148 #endif
149 		"exe_file %px\n"
150 #ifdef CONFIG_MMU_NOTIFIER
151 		"mmu_notifier_mm %px\n"
152 #endif
153 #ifdef CONFIG_NUMA_BALANCING
154 		"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
155 #endif
156 		"tlb_flush_pending %d\n"
157 		"def_flags: %#lx(%pGv)\n",
158 
159 		mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
160 #ifdef CONFIG_MMU
161 		mm->get_unmapped_area,
162 #endif
163 		mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
164 		mm->pgd, atomic_read(&mm->mm_users),
165 		atomic_read(&mm->mm_count),
166 		mm_pgtables_bytes(mm),
167 		mm->map_count,
168 		mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
169 		mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm,
170 		mm->start_code, mm->end_code, mm->start_data, mm->end_data,
171 		mm->start_brk, mm->brk, mm->start_stack,
172 		mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
173 		mm->binfmt, mm->flags, mm->core_state,
174 #ifdef CONFIG_AIO
175 		mm->ioctx_table,
176 #endif
177 #ifdef CONFIG_MEMCG
178 		mm->owner,
179 #endif
180 		mm->exe_file,
181 #ifdef CONFIG_MMU_NOTIFIER
182 		mm->mmu_notifier_mm,
183 #endif
184 #ifdef CONFIG_NUMA_BALANCING
185 		mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
186 #endif
187 		atomic_read(&mm->tlb_flush_pending),
188 		mm->def_flags, &mm->def_flags
189 	);
190 }
191 
192 static bool page_init_poisoning __read_mostly = true;
193 
194 static int __init setup_vm_debug(char *str)
195 {
196 	bool __page_init_poisoning = true;
197 
198 	/*
199 	 * Calling vm_debug with no arguments is equivalent to requesting
200 	 * to enable all debugging options we can control.
201 	 */
202 	if (*str++ != '=' || !*str)
203 		goto out;
204 
205 	__page_init_poisoning = false;
206 	if (*str == '-')
207 		goto out;
208 
209 	while (*str) {
210 		switch (tolower(*str)) {
211 		case'p':
212 			__page_init_poisoning = true;
213 			break;
214 		default:
215 			pr_err("vm_debug option '%c' unknown. skipped\n",
216 			       *str);
217 		}
218 
219 		str++;
220 	}
221 out:
222 	if (page_init_poisoning && !__page_init_poisoning)
223 		pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
224 
225 	page_init_poisoning = __page_init_poisoning;
226 
227 	return 1;
228 }
229 __setup("vm_debug", setup_vm_debug);
230 
231 void page_init_poison(struct page *page, size_t size)
232 {
233 	if (page_init_poisoning)
234 		memset(page, PAGE_POISON_PATTERN, size);
235 }
236 EXPORT_SYMBOL_GPL(page_init_poison);
237 #endif		/* CONFIG_DEBUG_VM */
238