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 20 const char *migrate_reason_names[MR_TYPES] = { 21 "compaction", 22 "memory_failure", 23 "memory_hotplug", 24 "syscall_or_cpuset", 25 "mempolicy_mbind", 26 "numa_misplaced", 27 "cma", 28 }; 29 30 const struct trace_print_flags pageflag_names[] = { 31 __def_pageflag_names, 32 {0, NULL} 33 }; 34 35 const struct trace_print_flags gfpflag_names[] = { 36 __def_gfpflag_names, 37 {0, NULL} 38 }; 39 40 const struct trace_print_flags vmaflag_names[] = { 41 __def_vmaflag_names, 42 {0, NULL} 43 }; 44 45 void __dump_page(struct page *page, const char *reason) 46 { 47 struct address_space *mapping; 48 bool page_poisoned = PagePoisoned(page); 49 /* 50 * Accessing the pageblock without the zone lock. It could change to 51 * "isolate" again in the meantime, but since we are just dumping the 52 * state for debugging, it should be fine to accept a bit of 53 * inaccuracy here due to racing. 54 */ 55 bool page_cma = is_migrate_cma_page(page); 56 int mapcount; 57 char *type = ""; 58 59 /* 60 * If struct page is poisoned don't access Page*() functions as that 61 * leads to recursive loop. Page*() check for poisoned pages, and calls 62 * dump_page() when detected. 63 */ 64 if (page_poisoned) { 65 pr_warn("page:%px is uninitialized and poisoned", page); 66 goto hex_only; 67 } 68 69 mapping = page_mapping(page); 70 71 /* 72 * Avoid VM_BUG_ON() in page_mapcount(). 73 * page->_mapcount space in struct page is used by sl[aou]b pages to 74 * encode own info. 75 */ 76 mapcount = PageSlab(page) ? 0 : page_mapcount(page); 77 78 if (PageCompound(page)) 79 pr_warn("page:%px refcount:%d mapcount:%d mapping:%px " 80 "index:%#lx compound_mapcount: %d\n", 81 page, page_ref_count(page), mapcount, 82 page->mapping, page_to_pgoff(page), 83 compound_mapcount(page)); 84 else 85 pr_warn("page:%px refcount:%d mapcount:%d mapping:%px index:%#lx\n", 86 page, page_ref_count(page), mapcount, 87 page->mapping, page_to_pgoff(page)); 88 if (PageKsm(page)) 89 type = "ksm "; 90 else if (PageAnon(page)) 91 type = "anon "; 92 else if (mapping) { 93 if (mapping->host && mapping->host->i_dentry.first) { 94 struct dentry *dentry; 95 dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias); 96 pr_warn("%ps name:\"%pd\"\n", mapping->a_ops, dentry); 97 } else 98 pr_warn("%ps\n", mapping->a_ops); 99 } 100 BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); 101 102 pr_warn("%sflags: %#lx(%pGp)%s\n", type, page->flags, &page->flags, 103 page_cma ? " CMA" : ""); 104 105 hex_only: 106 print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32, 107 sizeof(unsigned long), page, 108 sizeof(struct page), false); 109 110 if (reason) 111 pr_warn("page dumped because: %s\n", reason); 112 113 #ifdef CONFIG_MEMCG 114 if (!page_poisoned && page->mem_cgroup) 115 pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup); 116 #endif 117 } 118 119 void dump_page(struct page *page, const char *reason) 120 { 121 __dump_page(page, reason); 122 dump_page_owner(page); 123 } 124 EXPORT_SYMBOL(dump_page); 125 126 #ifdef CONFIG_DEBUG_VM 127 128 void dump_vma(const struct vm_area_struct *vma) 129 { 130 pr_emerg("vma %px start %px end %px\n" 131 "next %px prev %px mm %px\n" 132 "prot %lx anon_vma %px vm_ops %px\n" 133 "pgoff %lx file %px private_data %px\n" 134 "flags: %#lx(%pGv)\n", 135 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next, 136 vma->vm_prev, vma->vm_mm, 137 (unsigned long)pgprot_val(vma->vm_page_prot), 138 vma->anon_vma, vma->vm_ops, vma->vm_pgoff, 139 vma->vm_file, vma->vm_private_data, 140 vma->vm_flags, &vma->vm_flags); 141 } 142 EXPORT_SYMBOL(dump_vma); 143 144 void dump_mm(const struct mm_struct *mm) 145 { 146 pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n" 147 #ifdef CONFIG_MMU 148 "get_unmapped_area %px\n" 149 #endif 150 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n" 151 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n" 152 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" 153 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n" 154 "start_code %lx end_code %lx start_data %lx end_data %lx\n" 155 "start_brk %lx brk %lx start_stack %lx\n" 156 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n" 157 "binfmt %px flags %lx core_state %px\n" 158 #ifdef CONFIG_AIO 159 "ioctx_table %px\n" 160 #endif 161 #ifdef CONFIG_MEMCG 162 "owner %px " 163 #endif 164 "exe_file %px\n" 165 #ifdef CONFIG_MMU_NOTIFIER 166 "notifier_subscriptions %px\n" 167 #endif 168 #ifdef CONFIG_NUMA_BALANCING 169 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n" 170 #endif 171 "tlb_flush_pending %d\n" 172 "def_flags: %#lx(%pGv)\n", 173 174 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size, 175 #ifdef CONFIG_MMU 176 mm->get_unmapped_area, 177 #endif 178 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end, 179 mm->pgd, atomic_read(&mm->mm_users), 180 atomic_read(&mm->mm_count), 181 mm_pgtables_bytes(mm), 182 mm->map_count, 183 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, 184 (u64)atomic64_read(&mm->pinned_vm), 185 mm->data_vm, mm->exec_vm, mm->stack_vm, 186 mm->start_code, mm->end_code, mm->start_data, mm->end_data, 187 mm->start_brk, mm->brk, mm->start_stack, 188 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end, 189 mm->binfmt, mm->flags, mm->core_state, 190 #ifdef CONFIG_AIO 191 mm->ioctx_table, 192 #endif 193 #ifdef CONFIG_MEMCG 194 mm->owner, 195 #endif 196 mm->exe_file, 197 #ifdef CONFIG_MMU_NOTIFIER 198 mm->notifier_subscriptions, 199 #endif 200 #ifdef CONFIG_NUMA_BALANCING 201 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq, 202 #endif 203 atomic_read(&mm->tlb_flush_pending), 204 mm->def_flags, &mm->def_flags 205 ); 206 } 207 208 static bool page_init_poisoning __read_mostly = true; 209 210 static int __init setup_vm_debug(char *str) 211 { 212 bool __page_init_poisoning = true; 213 214 /* 215 * Calling vm_debug with no arguments is equivalent to requesting 216 * to enable all debugging options we can control. 217 */ 218 if (*str++ != '=' || !*str) 219 goto out; 220 221 __page_init_poisoning = false; 222 if (*str == '-') 223 goto out; 224 225 while (*str) { 226 switch (tolower(*str)) { 227 case'p': 228 __page_init_poisoning = true; 229 break; 230 default: 231 pr_err("vm_debug option '%c' unknown. skipped\n", 232 *str); 233 } 234 235 str++; 236 } 237 out: 238 if (page_init_poisoning && !__page_init_poisoning) 239 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n"); 240 241 page_init_poisoning = __page_init_poisoning; 242 243 return 1; 244 } 245 __setup("vm_debug", setup_vm_debug); 246 247 void page_init_poison(struct page *page, size_t size) 248 { 249 if (page_init_poisoning) 250 memset(page, PAGE_POISON_PATTERN, size); 251 } 252 EXPORT_SYMBOL_GPL(page_init_poison); 253 #endif /* CONFIG_DEBUG_VM */ 254