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 gfpflag_names[] = { 40 __def_gfpflag_names, 41 {0, NULL} 42 }; 43 44 const struct trace_print_flags vmaflag_names[] = { 45 __def_vmaflag_names, 46 {0, NULL} 47 }; 48 49 static void __dump_page(struct page *page) 50 { 51 struct folio *folio = page_folio(page); 52 struct page *head = &folio->page; 53 struct address_space *mapping; 54 bool compound = PageCompound(page); 55 /* 56 * Accessing the pageblock without the zone lock. It could change to 57 * "isolate" again in the meantime, but since we are just dumping the 58 * state for debugging, it should be fine to accept a bit of 59 * inaccuracy here due to racing. 60 */ 61 bool page_cma = is_migrate_cma_page(page); 62 int mapcount; 63 char *type = ""; 64 65 if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) { 66 /* 67 * Corrupt page, so we cannot call page_mapping. Instead, do a 68 * safe subset of the steps that page_mapping() does. Caution: 69 * this will be misleading for tail pages, PageSwapCache pages, 70 * and potentially other situations. (See the page_mapping() 71 * implementation for what's missing here.) 72 */ 73 unsigned long tmp = (unsigned long)page->mapping; 74 75 if (tmp & PAGE_MAPPING_ANON) 76 mapping = NULL; 77 else 78 mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS); 79 head = page; 80 folio = (struct folio *)page; 81 compound = false; 82 } else { 83 mapping = page_mapping(page); 84 } 85 86 /* 87 * Avoid VM_BUG_ON() in page_mapcount(). 88 * page->_mapcount space in struct page is used by sl[aou]b pages to 89 * encode own info. 90 */ 91 mapcount = PageSlab(head) ? 0 : page_mapcount(page); 92 93 pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n", 94 page, page_ref_count(head), mapcount, mapping, 95 page_to_pgoff(page), page_to_pfn(page)); 96 if (compound) { 97 pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n", 98 head, compound_order(head), 99 folio_entire_mapcount(folio), 100 head_compound_pincount(head)); 101 } 102 103 #ifdef CONFIG_MEMCG 104 if (head->memcg_data) 105 pr_warn("memcg:%lx\n", head->memcg_data); 106 #endif 107 if (PageKsm(page)) 108 type = "ksm "; 109 else if (PageAnon(page)) 110 type = "anon "; 111 else if (mapping) 112 dump_mapping(mapping); 113 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); 114 115 pr_warn("%sflags: %pGp%s\n", type, &head->flags, 116 page_cma ? " CMA" : ""); 117 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32, 118 sizeof(unsigned long), page, 119 sizeof(struct page), false); 120 if (head != page) 121 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32, 122 sizeof(unsigned long), head, 123 sizeof(struct page), false); 124 } 125 126 void dump_page(struct page *page, const char *reason) 127 { 128 if (PagePoisoned(page)) 129 pr_warn("page:%p is uninitialized and poisoned", page); 130 else 131 __dump_page(page); 132 if (reason) 133 pr_warn("page dumped because: %s\n", reason); 134 dump_page_owner(page); 135 } 136 EXPORT_SYMBOL(dump_page); 137 138 #ifdef CONFIG_DEBUG_VM 139 140 void dump_vma(const struct vm_area_struct *vma) 141 { 142 pr_emerg("vma %px start %px end %px mm %px\n" 143 "prot %lx anon_vma %px vm_ops %px\n" 144 "pgoff %lx file %px private_data %px\n" 145 "flags: %#lx(%pGv)\n", 146 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm, 147 (unsigned long)pgprot_val(vma->vm_page_prot), 148 vma->anon_vma, vma->vm_ops, vma->vm_pgoff, 149 vma->vm_file, vma->vm_private_data, 150 vma->vm_flags, &vma->vm_flags); 151 } 152 EXPORT_SYMBOL(dump_vma); 153 154 void dump_mm(const struct mm_struct *mm) 155 { 156 pr_emerg("mm %px task_size %lu\n" 157 #ifdef CONFIG_MMU 158 "get_unmapped_area %px\n" 159 #endif 160 "mmap_base %lu mmap_legacy_base %lu\n" 161 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n" 162 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" 163 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n" 164 "start_code %lx end_code %lx start_data %lx end_data %lx\n" 165 "start_brk %lx brk %lx start_stack %lx\n" 166 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n" 167 "binfmt %px flags %lx\n" 168 #ifdef CONFIG_AIO 169 "ioctx_table %px\n" 170 #endif 171 #ifdef CONFIG_MEMCG 172 "owner %px " 173 #endif 174 "exe_file %px\n" 175 #ifdef CONFIG_MMU_NOTIFIER 176 "notifier_subscriptions %px\n" 177 #endif 178 #ifdef CONFIG_NUMA_BALANCING 179 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n" 180 #endif 181 "tlb_flush_pending %d\n" 182 "def_flags: %#lx(%pGv)\n", 183 184 mm, mm->task_size, 185 #ifdef CONFIG_MMU 186 mm->get_unmapped_area, 187 #endif 188 mm->mmap_base, mm->mmap_legacy_base, 189 mm->pgd, atomic_read(&mm->mm_users), 190 atomic_read(&mm->mm_count), 191 mm_pgtables_bytes(mm), 192 mm->map_count, 193 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, 194 (u64)atomic64_read(&mm->pinned_vm), 195 mm->data_vm, mm->exec_vm, mm->stack_vm, 196 mm->start_code, mm->end_code, mm->start_data, mm->end_data, 197 mm->start_brk, mm->brk, mm->start_stack, 198 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end, 199 mm->binfmt, mm->flags, 200 #ifdef CONFIG_AIO 201 mm->ioctx_table, 202 #endif 203 #ifdef CONFIG_MEMCG 204 mm->owner, 205 #endif 206 mm->exe_file, 207 #ifdef CONFIG_MMU_NOTIFIER 208 mm->notifier_subscriptions, 209 #endif 210 #ifdef CONFIG_NUMA_BALANCING 211 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq, 212 #endif 213 atomic_read(&mm->tlb_flush_pending), 214 mm->def_flags, &mm->def_flags 215 ); 216 } 217 218 static bool page_init_poisoning __read_mostly = true; 219 220 static int __init setup_vm_debug(char *str) 221 { 222 bool __page_init_poisoning = true; 223 224 /* 225 * Calling vm_debug with no arguments is equivalent to requesting 226 * to enable all debugging options we can control. 227 */ 228 if (*str++ != '=' || !*str) 229 goto out; 230 231 __page_init_poisoning = false; 232 if (*str == '-') 233 goto out; 234 235 while (*str) { 236 switch (tolower(*str)) { 237 case'p': 238 __page_init_poisoning = true; 239 break; 240 default: 241 pr_err("vm_debug option '%c' unknown. skipped\n", 242 *str); 243 } 244 245 str++; 246 } 247 out: 248 if (page_init_poisoning && !__page_init_poisoning) 249 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n"); 250 251 page_init_poisoning = __page_init_poisoning; 252 253 return 1; 254 } 255 __setup("vm_debug", setup_vm_debug); 256 257 void page_init_poison(struct page *page, size_t size) 258 { 259 if (page_init_poisoning) 260 memset(page, PAGE_POISON_PATTERN, size); 261 } 262 #endif /* CONFIG_DEBUG_VM */ 263