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 */ 272