| 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 | #include <trace/events/migrate.h> |
| 20 | |
| 21 | /* |
| 22 | * Define EM() and EMe() so that MIGRATE_REASON from trace/events/migrate.h can |
| 23 | * be used to populate migrate_reason_names[]. |
| 24 | */ |
| 25 | #undef EM |
| 26 | #undef EMe |
| 27 | #define EM(a, b) b, |
| 28 | #define EMe(a, b) b |
| 29 | |
| 30 | const char *migrate_reason_names[MR_TYPES] = { |
| 31 | MIGRATE_REASON |
| 32 | }; |
| 33 | |
| 34 | const struct trace_print_flags pageflag_names[] = { |
| 35 | __def_pageflag_names, |
| 36 | {0, NULL} |
| 37 | }; |
| 38 | |
| 39 | const struct trace_print_flags pagetype_names[] = { |
| 40 | __def_pagetype_names, |
| 41 | {0, NULL} |
| 42 | }; |
| 43 | |
| 44 | const struct trace_print_flags gfpflag_names[] = { |
| 45 | __def_gfpflag_names, |
| 46 | {0, NULL} |
| 47 | }; |
| 48 | |
| 49 | const struct trace_print_flags vmaflag_names[] = { |
| 50 | __def_vmaflag_names, |
| 51 | {0, NULL} |
| 52 | }; |
| 53 | |
| 54 | static void __dump_page(struct page *page) |
| 55 | { |
| 56 | struct folio *folio = page_folio(page); |
| 57 | struct page *head = &folio->page; |
| 58 | struct address_space *mapping; |
| 59 | bool compound = PageCompound(page); |
| 60 | /* |
| 61 | * Accessing the pageblock without the zone lock. It could change to |
| 62 | * "isolate" again in the meantime, but since we are just dumping the |
| 63 | * state for debugging, it should be fine to accept a bit of |
| 64 | * inaccuracy here due to racing. |
| 65 | */ |
| 66 | bool page_cma = is_migrate_cma_page(page); |
| 67 | int mapcount; |
| 68 | char *type = ""; |
| 69 | |
| 70 | if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) { |
| 71 | /* |
| 72 | * Corrupt page, so we cannot call page_mapping. Instead, do a |
| 73 | * safe subset of the steps that page_mapping() does. Caution: |
| 74 | * this will be misleading for tail pages, PageSwapCache pages, |
| 75 | * and potentially other situations. (See the page_mapping() |
| 76 | * implementation for what's missing here.) |
| 77 | */ |
| 78 | unsigned long tmp = (unsigned long)page->mapping; |
| 79 | |
| 80 | if (tmp & PAGE_MAPPING_ANON) |
| 81 | mapping = NULL; |
| 82 | else |
| 83 | mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS); |
| 84 | head = page; |
| 85 | folio = (struct folio *)page; |
| 86 | compound = false; |
| 87 | } else { |
| 88 | mapping = page_mapping(page); |
| 89 | } |
| 90 | |
| 91 | /* |
| 92 | * Avoid VM_BUG_ON() in page_mapcount(). |
| 93 | * page->_mapcount space in struct page is used by sl[aou]b pages to |
| 94 | * encode own info. |
| 95 | */ |
| 96 | mapcount = PageSlab(head) ? 0 : page_mapcount(page); |
| 97 | |
| 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)); |
| 101 | if (compound) { |
| 102 | pr_warn("head:%p order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n", |
| 103 | head, compound_order(head), |
| 104 | folio_entire_mapcount(folio), |
| 105 | folio_nr_pages_mapped(folio), |
| 106 | atomic_read(&folio->_pincount)); |
| 107 | } |
| 108 | |
| 109 | #ifdef CONFIG_MEMCG |
| 110 | if (head->memcg_data) |
| 111 | pr_warn("memcg:%lx\n", head->memcg_data); |
| 112 | #endif |
| 113 | if (PageKsm(page)) |
| 114 | type = "ksm "; |
| 115 | else if (PageAnon(page)) |
| 116 | type = "anon "; |
| 117 | else if (mapping) |
| 118 | dump_mapping(mapping); |
| 119 | BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); |
| 120 | |
| 121 | pr_warn("%sflags: %pGp%s\n", type, &head->flags, |
| 122 | page_cma ? " CMA" : ""); |
| 123 | pr_warn("page_type: %pGt\n", &head->page_type); |
| 124 | |
| 125 | print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32, |
| 126 | sizeof(unsigned long), page, |
| 127 | sizeof(struct page), false); |
| 128 | if (head != page) |
| 129 | print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32, |
| 130 | sizeof(unsigned long), head, |
| 131 | sizeof(struct page), false); |
| 132 | } |
| 133 | |
| 134 | void dump_page(struct page *page, const char *reason) |
| 135 | { |
| 136 | if (PagePoisoned(page)) |
| 137 | pr_warn("page:%p is uninitialized and poisoned", page); |
| 138 | else |
| 139 | __dump_page(page); |
| 140 | if (reason) |
| 141 | pr_warn("page dumped because: %s\n", reason); |
| 142 | dump_page_owner(page); |
| 143 | } |
| 144 | EXPORT_SYMBOL(dump_page); |
| 145 | |
| 146 | #ifdef CONFIG_DEBUG_VM |
| 147 | |
| 148 | void dump_vma(const struct vm_area_struct *vma) |
| 149 | { |
| 150 | pr_emerg("vma %px start %px end %px mm %px\n" |
| 151 | "prot %lx anon_vma %px vm_ops %px\n" |
| 152 | "pgoff %lx file %px private_data %px\n" |
| 153 | "flags: %#lx(%pGv)\n", |
| 154 | vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm, |
| 155 | (unsigned long)pgprot_val(vma->vm_page_prot), |
| 156 | vma->anon_vma, vma->vm_ops, vma->vm_pgoff, |
| 157 | vma->vm_file, vma->vm_private_data, |
| 158 | vma->vm_flags, &vma->vm_flags); |
| 159 | } |
| 160 | EXPORT_SYMBOL(dump_vma); |
| 161 | |
| 162 | void dump_mm(const struct mm_struct *mm) |
| 163 | { |
| 164 | pr_emerg("mm %px task_size %lu\n" |
| 165 | #ifdef CONFIG_MMU |
| 166 | "get_unmapped_area %px\n" |
| 167 | #endif |
| 168 | "mmap_base %lu mmap_legacy_base %lu\n" |
| 169 | "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n" |
| 170 | "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" |
| 171 | "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n" |
| 172 | "start_code %lx end_code %lx start_data %lx end_data %lx\n" |
| 173 | "start_brk %lx brk %lx start_stack %lx\n" |
| 174 | "arg_start %lx arg_end %lx env_start %lx env_end %lx\n" |
| 175 | "binfmt %px flags %lx\n" |
| 176 | #ifdef CONFIG_AIO |
| 177 | "ioctx_table %px\n" |
| 178 | #endif |
| 179 | #ifdef CONFIG_MEMCG |
| 180 | "owner %px " |
| 181 | #endif |
| 182 | "exe_file %px\n" |
| 183 | #ifdef CONFIG_MMU_NOTIFIER |
| 184 | "notifier_subscriptions %px\n" |
| 185 | #endif |
| 186 | #ifdef CONFIG_NUMA_BALANCING |
| 187 | "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n" |
| 188 | #endif |
| 189 | "tlb_flush_pending %d\n" |
| 190 | "def_flags: %#lx(%pGv)\n", |
| 191 | |
| 192 | mm, mm->task_size, |
| 193 | #ifdef CONFIG_MMU |
| 194 | mm->get_unmapped_area, |
| 195 | #endif |
| 196 | mm->mmap_base, mm->mmap_legacy_base, |
| 197 | mm->pgd, atomic_read(&mm->mm_users), |
| 198 | atomic_read(&mm->mm_count), |
| 199 | mm_pgtables_bytes(mm), |
| 200 | mm->map_count, |
| 201 | mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, |
| 202 | (u64)atomic64_read(&mm->pinned_vm), |
| 203 | mm->data_vm, mm->exec_vm, mm->stack_vm, |
| 204 | mm->start_code, mm->end_code, mm->start_data, mm->end_data, |
| 205 | mm->start_brk, mm->brk, mm->start_stack, |
| 206 | mm->arg_start, mm->arg_end, mm->env_start, mm->env_end, |
| 207 | mm->binfmt, mm->flags, |
| 208 | #ifdef CONFIG_AIO |
| 209 | mm->ioctx_table, |
| 210 | #endif |
| 211 | #ifdef CONFIG_MEMCG |
| 212 | mm->owner, |
| 213 | #endif |
| 214 | mm->exe_file, |
| 215 | #ifdef CONFIG_MMU_NOTIFIER |
| 216 | mm->notifier_subscriptions, |
| 217 | #endif |
| 218 | #ifdef CONFIG_NUMA_BALANCING |
| 219 | mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq, |
| 220 | #endif |
| 221 | atomic_read(&mm->tlb_flush_pending), |
| 222 | mm->def_flags, &mm->def_flags |
| 223 | ); |
| 224 | } |
| 225 | EXPORT_SYMBOL(dump_mm); |
| 226 | |
| 227 | static bool page_init_poisoning __read_mostly = true; |
| 228 | |
| 229 | static int __init setup_vm_debug(char *str) |
| 230 | { |
| 231 | bool __page_init_poisoning = true; |
| 232 | |
| 233 | /* |
| 234 | * Calling vm_debug with no arguments is equivalent to requesting |
| 235 | * to enable all debugging options we can control. |
| 236 | */ |
| 237 | if (*str++ != '=' || !*str) |
| 238 | goto out; |
| 239 | |
| 240 | __page_init_poisoning = false; |
| 241 | if (*str == '-') |
| 242 | goto out; |
| 243 | |
| 244 | while (*str) { |
| 245 | switch (tolower(*str)) { |
| 246 | case'p': |
| 247 | __page_init_poisoning = true; |
| 248 | break; |
| 249 | default: |
| 250 | pr_err("vm_debug option '%c' unknown. skipped\n", |
| 251 | *str); |
| 252 | } |
| 253 | |
| 254 | str++; |
| 255 | } |
| 256 | out: |
| 257 | if (page_init_poisoning && !__page_init_poisoning) |
| 258 | pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n"); |
| 259 | |
| 260 | page_init_poisoning = __page_init_poisoning; |
| 261 | |
| 262 | return 1; |
| 263 | } |
| 264 | __setup("vm_debug", setup_vm_debug); |
| 265 | |
| 266 | void page_init_poison(struct page *page, size_t size) |
| 267 | { |
| 268 | if (page_init_poisoning) |
| 269 | memset(page, PAGE_POISON_PATTERN, size); |
| 270 | } |
| 271 | #endif /* CONFIG_DEBUG_VM */ |