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 void __dump_page(struct page
*page
, const char *reason
)
47 struct page
*head
= compound_head(page
);
48 struct address_space
*mapping
;
49 bool page_poisoned
= PagePoisoned(page
);
50 bool compound
= PageCompound(page
);
52 * Accessing the pageblock without the zone lock. It could change to
53 * "isolate" again in the meantime, but since we are just dumping the
54 * state for debugging, it should be fine to accept a bit of
55 * inaccuracy here due to racing.
57 bool page_cma
= is_migrate_cma_page(page
);
62 * If struct page is poisoned don't access Page*() functions as that
63 * leads to recursive loop. Page*() check for poisoned pages, and calls
64 * dump_page() when detected.
67 pr_warn("page:%px is uninitialized and poisoned", page
);
71 if (page
< head
|| (page
>= head
+ MAX_ORDER_NR_PAGES
)) {
73 * Corrupt page, so we cannot call page_mapping. Instead, do a
74 * safe subset of the steps that page_mapping() does. Caution:
75 * this will be misleading for tail pages, PageSwapCache pages,
76 * and potentially other situations. (See the page_mapping()
77 * implementation for what's missing here.)
79 unsigned long tmp
= (unsigned long)page
->mapping
;
81 if (tmp
& PAGE_MAPPING_ANON
)
84 mapping
= (void *)(tmp
& ~PAGE_MAPPING_FLAGS
);
88 mapping
= page_mapping(page
);
92 * Avoid VM_BUG_ON() in page_mapcount().
93 * page->_mapcount space in struct page is used by sl[aou]b pages to
96 mapcount
= PageSlab(head
) ? 0 : page_mapcount(page
);
98 pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
99 page
, page_ref_count(head
), mapcount
, mapping
,
100 page_to_pgoff(page
), page_to_pfn(page
));
102 if (hpage_pincount_available(page
)) {
103 pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
104 head
, compound_order(head
),
105 head_compound_mapcount(head
),
106 head_compound_pincount(head
));
108 pr_warn("head:%p order:%u compound_mapcount:%d\n",
109 head
, compound_order(head
),
110 head_compound_mapcount(head
));
115 if (head
->memcg_data
)
116 pr_warn("memcg:%lx\n", head
->memcg_data
);
120 else if (PageAnon(page
))
124 const struct address_space_operations
*a_ops
;
125 struct hlist_node
*dentry_first
;
126 struct dentry
*dentry_ptr
;
127 struct dentry dentry
;
131 * mapping can be invalid pointer and we don't want to crash
132 * accessing it, so probe everything depending on it carefully
134 if (get_kernel_nofault(host
, &mapping
->host
) ||
135 get_kernel_nofault(a_ops
, &mapping
->a_ops
)) {
136 pr_warn("failed to read mapping contents, not a valid kernel address?\n");
141 pr_warn("aops:%ps\n", a_ops
);
145 if (get_kernel_nofault(dentry_first
, &host
->i_dentry
.first
) ||
146 get_kernel_nofault(ino
, &host
->i_ino
)) {
147 pr_warn("aops:%ps with invalid host inode %px\n",
153 pr_warn("aops:%ps ino:%lx\n", a_ops
, ino
);
157 dentry_ptr
= container_of(dentry_first
, struct dentry
, d_u
.d_alias
);
158 if (get_kernel_nofault(dentry
, dentry_ptr
)) {
159 pr_warn("aops:%ps ino:%lx with invalid dentry %px\n",
160 a_ops
, ino
, dentry_ptr
);
163 * if dentry is corrupted, the %pd handler may still
164 * crash, but it's unlikely that we reach here with a
165 * corrupted struct page
167 pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n",
168 a_ops
, ino
, &dentry
);
172 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names
) != __NR_PAGEFLAGS
+ 1);
174 pr_warn("%sflags: %#lx(%pGp)%s\n", type
, head
->flags
, &head
->flags
,
175 page_cma
? " CMA" : "");
178 print_hex_dump(KERN_WARNING
, "raw: ", DUMP_PREFIX_NONE
, 32,
179 sizeof(unsigned long), page
,
180 sizeof(struct page
), false);
182 print_hex_dump(KERN_WARNING
, "head: ", DUMP_PREFIX_NONE
, 32,
183 sizeof(unsigned long), head
,
184 sizeof(struct page
), false);
187 pr_warn("page dumped because: %s\n", reason
);
190 void dump_page(struct page
*page
, const char *reason
)
192 __dump_page(page
, reason
);
193 dump_page_owner(page
);
195 EXPORT_SYMBOL(dump_page
);
197 #ifdef CONFIG_DEBUG_VM
199 void dump_vma(const struct vm_area_struct
*vma
)
201 pr_emerg("vma %px start %px end %px\n"
202 "next %px prev %px mm %px\n"
203 "prot %lx anon_vma %px vm_ops %px\n"
204 "pgoff %lx file %px private_data %px\n"
205 "flags: %#lx(%pGv)\n",
206 vma
, (void *)vma
->vm_start
, (void *)vma
->vm_end
, vma
->vm_next
,
207 vma
->vm_prev
, vma
->vm_mm
,
208 (unsigned long)pgprot_val(vma
->vm_page_prot
),
209 vma
->anon_vma
, vma
->vm_ops
, vma
->vm_pgoff
,
210 vma
->vm_file
, vma
->vm_private_data
,
211 vma
->vm_flags
, &vma
->vm_flags
);
213 EXPORT_SYMBOL(dump_vma
);
215 void dump_mm(const struct mm_struct
*mm
)
217 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
219 "get_unmapped_area %px\n"
221 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
222 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
223 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
224 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
225 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
226 "start_brk %lx brk %lx start_stack %lx\n"
227 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
228 "binfmt %px flags %lx core_state %px\n"
236 #ifdef CONFIG_MMU_NOTIFIER
237 "notifier_subscriptions %px\n"
239 #ifdef CONFIG_NUMA_BALANCING
240 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
242 "tlb_flush_pending %d\n"
243 "def_flags: %#lx(%pGv)\n",
245 mm
, mm
->mmap
, (long long) mm
->vmacache_seqnum
, mm
->task_size
,
247 mm
->get_unmapped_area
,
249 mm
->mmap_base
, mm
->mmap_legacy_base
, mm
->highest_vm_end
,
250 mm
->pgd
, atomic_read(&mm
->mm_users
),
251 atomic_read(&mm
->mm_count
),
252 mm_pgtables_bytes(mm
),
254 mm
->hiwater_rss
, mm
->hiwater_vm
, mm
->total_vm
, mm
->locked_vm
,
255 (u64
)atomic64_read(&mm
->pinned_vm
),
256 mm
->data_vm
, mm
->exec_vm
, mm
->stack_vm
,
257 mm
->start_code
, mm
->end_code
, mm
->start_data
, mm
->end_data
,
258 mm
->start_brk
, mm
->brk
, mm
->start_stack
,
259 mm
->arg_start
, mm
->arg_end
, mm
->env_start
, mm
->env_end
,
260 mm
->binfmt
, mm
->flags
, mm
->core_state
,
268 #ifdef CONFIG_MMU_NOTIFIER
269 mm
->notifier_subscriptions
,
271 #ifdef CONFIG_NUMA_BALANCING
272 mm
->numa_next_scan
, mm
->numa_scan_offset
, mm
->numa_scan_seq
,
274 atomic_read(&mm
->tlb_flush_pending
),
275 mm
->def_flags
, &mm
->def_flags
279 static bool page_init_poisoning __read_mostly
= true;
281 static int __init
setup_vm_debug(char *str
)
283 bool __page_init_poisoning
= true;
286 * Calling vm_debug with no arguments is equivalent to requesting
287 * to enable all debugging options we can control.
289 if (*str
++ != '=' || !*str
)
292 __page_init_poisoning
= false;
297 switch (tolower(*str
)) {
299 __page_init_poisoning
= true;
302 pr_err("vm_debug option '%c' unknown. skipped\n",
309 if (page_init_poisoning
&& !__page_init_poisoning
)
310 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
312 page_init_poisoning
= __page_init_poisoning
;
316 __setup("vm_debug", setup_vm_debug
);
318 void page_init_poison(struct page
*page
, size_t size
)
320 if (page_init_poisoning
)
321 memset(page
, PAGE_POISON_PATTERN
, size
);
323 EXPORT_SYMBOL_GPL(page_init_poison
);
324 #endif /* CONFIG_DEBUG_VM */