1 // SPDX-License-Identifier: GPL-2.0
5 * mm/ specific debug routines.
9 #include <linux/kernel.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>
20 const char *migrate_reason_names
[MR_TYPES
] = {
30 const struct trace_print_flags pageflag_names
[] = {
35 const struct trace_print_flags gfpflag_names
[] = {
40 const struct trace_print_flags vmaflag_names
[] = {
45 static void __dump_page(struct page
*page
)
47 struct page
*head
= compound_head(page
);
48 struct address_space
*mapping
;
49 bool compound
= PageCompound(page
);
51 * Accessing the pageblock without the zone lock. It could change to
52 * "isolate" again in the meantime, but since we are just dumping the
53 * state for debugging, it should be fine to accept a bit of
54 * inaccuracy here due to racing.
56 bool page_cma
= is_migrate_cma_page(page
);
60 if (page
< head
|| (page
>= head
+ MAX_ORDER_NR_PAGES
)) {
62 * Corrupt page, so we cannot call page_mapping. Instead, do a
63 * safe subset of the steps that page_mapping() does. Caution:
64 * this will be misleading for tail pages, PageSwapCache pages,
65 * and potentially other situations. (See the page_mapping()
66 * implementation for what's missing here.)
68 unsigned long tmp
= (unsigned long)page
->mapping
;
70 if (tmp
& PAGE_MAPPING_ANON
)
73 mapping
= (void *)(tmp
& ~PAGE_MAPPING_FLAGS
);
77 mapping
= page_mapping(page
);
81 * Avoid VM_BUG_ON() in page_mapcount().
82 * page->_mapcount space in struct page is used by sl[aou]b pages to
85 mapcount
= PageSlab(head
) ? 0 : page_mapcount(page
);
87 pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
88 page
, page_ref_count(head
), mapcount
, mapping
,
89 page_to_pgoff(page
), page_to_pfn(page
));
91 if (hpage_pincount_available(page
)) {
92 pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
93 head
, compound_order(head
),
94 head_compound_mapcount(head
),
95 head_compound_pincount(head
));
97 pr_warn("head:%p order:%u compound_mapcount:%d\n",
98 head
, compound_order(head
),
99 head_compound_mapcount(head
));
104 if (head
->memcg_data
)
105 pr_warn("memcg:%lx\n", head
->memcg_data
);
109 else if (PageAnon(page
))
113 const struct address_space_operations
*a_ops
;
114 struct hlist_node
*dentry_first
;
115 struct dentry
*dentry_ptr
;
116 struct dentry dentry
;
120 * mapping can be invalid pointer and we don't want to crash
121 * accessing it, so probe everything depending on it carefully
123 if (get_kernel_nofault(host
, &mapping
->host
) ||
124 get_kernel_nofault(a_ops
, &mapping
->a_ops
)) {
125 pr_warn("failed to read mapping contents, not a valid kernel address?\n");
130 pr_warn("aops:%ps\n", a_ops
);
134 if (get_kernel_nofault(dentry_first
, &host
->i_dentry
.first
) ||
135 get_kernel_nofault(ino
, &host
->i_ino
)) {
136 pr_warn("aops:%ps with invalid host inode %px\n",
142 pr_warn("aops:%ps ino:%lx\n", a_ops
, ino
);
146 dentry_ptr
= container_of(dentry_first
, struct dentry
, d_u
.d_alias
);
147 if (get_kernel_nofault(dentry
, dentry_ptr
)) {
148 pr_warn("aops:%ps ino:%lx with invalid dentry %px\n",
149 a_ops
, ino
, dentry_ptr
);
152 * if dentry is corrupted, the %pd handler may still
153 * crash, but it's unlikely that we reach here with a
154 * corrupted struct page
156 pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
157 a_ops
, ino
, &dentry
);
161 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names
) != __NR_PAGEFLAGS
+ 1);
163 pr_warn("%sflags: %#lx(%pGp)%s\n", type
, head
->flags
, &head
->flags
,
164 page_cma
? " CMA" : "");
165 print_hex_dump(KERN_WARNING
, "raw: ", DUMP_PREFIX_NONE
, 32,
166 sizeof(unsigned long), page
,
167 sizeof(struct page
), false);
169 print_hex_dump(KERN_WARNING
, "head: ", DUMP_PREFIX_NONE
, 32,
170 sizeof(unsigned long), head
,
171 sizeof(struct page
), false);
174 void dump_page(struct page
*page
, const char *reason
)
176 if (PagePoisoned(page
))
177 pr_warn("page:%p is uninitialized and poisoned", page
);
181 pr_warn("page dumped because: %s\n", reason
);
182 dump_page_owner(page
);
184 EXPORT_SYMBOL(dump_page
);
186 #ifdef CONFIG_DEBUG_VM
188 void dump_vma(const struct vm_area_struct
*vma
)
190 pr_emerg("vma %px start %px end %px\n"
191 "next %px prev %px mm %px\n"
192 "prot %lx anon_vma %px vm_ops %px\n"
193 "pgoff %lx file %px private_data %px\n"
194 "flags: %#lx(%pGv)\n",
195 vma
, (void *)vma
->vm_start
, (void *)vma
->vm_end
, vma
->vm_next
,
196 vma
->vm_prev
, vma
->vm_mm
,
197 (unsigned long)pgprot_val(vma
->vm_page_prot
),
198 vma
->anon_vma
, vma
->vm_ops
, vma
->vm_pgoff
,
199 vma
->vm_file
, vma
->vm_private_data
,
200 vma
->vm_flags
, &vma
->vm_flags
);
202 EXPORT_SYMBOL(dump_vma
);
204 void dump_mm(const struct mm_struct
*mm
)
206 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
208 "get_unmapped_area %px\n"
210 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
211 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
212 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
213 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
214 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
215 "start_brk %lx brk %lx start_stack %lx\n"
216 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
217 "binfmt %px flags %lx core_state %px\n"
225 #ifdef CONFIG_MMU_NOTIFIER
226 "notifier_subscriptions %px\n"
228 #ifdef CONFIG_NUMA_BALANCING
229 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
231 "tlb_flush_pending %d\n"
232 "def_flags: %#lx(%pGv)\n",
234 mm
, mm
->mmap
, (long long) mm
->vmacache_seqnum
, mm
->task_size
,
236 mm
->get_unmapped_area
,
238 mm
->mmap_base
, mm
->mmap_legacy_base
, mm
->highest_vm_end
,
239 mm
->pgd
, atomic_read(&mm
->mm_users
),
240 atomic_read(&mm
->mm_count
),
241 mm_pgtables_bytes(mm
),
243 mm
->hiwater_rss
, mm
->hiwater_vm
, mm
->total_vm
, mm
->locked_vm
,
244 (u64
)atomic64_read(&mm
->pinned_vm
),
245 mm
->data_vm
, mm
->exec_vm
, mm
->stack_vm
,
246 mm
->start_code
, mm
->end_code
, mm
->start_data
, mm
->end_data
,
247 mm
->start_brk
, mm
->brk
, mm
->start_stack
,
248 mm
->arg_start
, mm
->arg_end
, mm
->env_start
, mm
->env_end
,
249 mm
->binfmt
, mm
->flags
, mm
->core_state
,
257 #ifdef CONFIG_MMU_NOTIFIER
258 mm
->notifier_subscriptions
,
260 #ifdef CONFIG_NUMA_BALANCING
261 mm
->numa_next_scan
, mm
->numa_scan_offset
, mm
->numa_scan_seq
,
263 atomic_read(&mm
->tlb_flush_pending
),
264 mm
->def_flags
, &mm
->def_flags
268 static bool page_init_poisoning __read_mostly
= true;
270 static int __init
setup_vm_debug(char *str
)
272 bool __page_init_poisoning
= true;
275 * Calling vm_debug with no arguments is equivalent to requesting
276 * to enable all debugging options we can control.
278 if (*str
++ != '=' || !*str
)
281 __page_init_poisoning
= false;
286 switch (tolower(*str
)) {
288 __page_init_poisoning
= true;
291 pr_err("vm_debug option '%c' unknown. skipped\n",
298 if (page_init_poisoning
&& !__page_init_poisoning
)
299 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
301 page_init_poisoning
= __page_init_poisoning
;
305 __setup("vm_debug", setup_vm_debug
);
307 void page_init_poison(struct page
*page
, size_t size
)
309 if (page_init_poisoning
)
310 memset(page
, PAGE_POISON_PATTERN
, size
);
312 EXPORT_SYMBOL_GPL(page_init_poison
);
313 #endif /* CONFIG_DEBUG_VM */