mm/debug.c

   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 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         bool page_poisoned = PagePoisoned(page);
  48         int mapcount;
  49
  50         /*
  51          * If struct page is poisoned don't access Page*() functions as that
  52          * leads to recursive loop. Page*() check for poisoned pages, and calls
  53          * dump_page() when detected.
  54          */
  55         if (page_poisoned) {
  56                 pr_emerg("page:%px is uninitialized and poisoned", page);
  57                 goto hex_only;
  58         }
  59
  60         /*
  61          * Avoid VM_BUG_ON() in page_mapcount().
  62          * page->_mapcount space in struct page is used by sl[aou]b pages to
  63          * encode own info.
  64          */
  65         mapcount = PageSlab(page) ? 0 : page_mapcount(page);
  66
  67         pr_emerg("page:%px count:%d mapcount:%d mapping:%px index:%#lx",
  68                   page, page_ref_count(page), mapcount,
  69                   page->mapping, page_to_pgoff(page));
  70         if (PageCompound(page))
  71                 pr_cont(" compound_mapcount: %d", compound_mapcount(page));
  72         pr_cont("\n");
  73         BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
  74
  75         pr_emerg("flags: %#lx(%pGp)\n", page->flags, &page->flags);
  76
  77 hex_only:
  78         print_hex_dump(KERN_ALERT, "raw: ", DUMP_PREFIX_NONE, 32,
  79                         sizeof(unsigned long), page,
  80                         sizeof(struct page), false);
  81
  82         if (reason)
  83                 pr_alert("page dumped because: %s\n", reason);
  84
  85 #ifdef CONFIG_MEMCG
  86         if (!page_poisoned && page->mem_cgroup)
  87                 pr_alert("page->mem_cgroup:%px\n", page->mem_cgroup);
  88 #endif
  89 }
  90
  91 void dump_page(struct page *page, const char *reason)
  92 {
  93         __dump_page(page, reason);
  94         dump_page_owner(page);
  95 }
  96 EXPORT_SYMBOL(dump_page);
  97
  98 #ifdef CONFIG_DEBUG_VM
  99
 100 void dump_vma(const struct vm_area_struct *vma)
 101 {
 102         pr_emerg("vma %px start %px end %px\n"
 103                 "next %px prev %px mm %px\n"
 104                 "prot %lx anon_vma %px vm_ops %px\n"
 105                 "pgoff %lx file %px private_data %px\n"
 106                 "flags: %#lx(%pGv)\n",
 107                 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
 108                 vma->vm_prev, vma->vm_mm,
 109                 (unsigned long)pgprot_val(vma->vm_page_prot),
 110                 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
 111                 vma->vm_file, vma->vm_private_data,
 112                 vma->vm_flags, &vma->vm_flags);
 113 }
 114 EXPORT_SYMBOL(dump_vma);
 115
 116 void dump_mm(const struct mm_struct *mm)
 117 {
 118         pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
 119 #ifdef CONFIG_MMU
 120                 "get_unmapped_area %px\n"
 121 #endif
 122                 "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
 123                 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
 124                 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
 125                 "pinned_vm %lx data_vm %lx exec_vm %lx stack_vm %lx\n"
 126                 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
 127                 "start_brk %lx brk %lx start_stack %lx\n"
 128                 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
 129                 "binfmt %px flags %lx core_state %px\n"
 130 #ifdef CONFIG_AIO
 131                 "ioctx_table %px\n"
 132 #endif
 133 #ifdef CONFIG_MEMCG
 134                 "owner %px "
 135 #endif
 136                 "exe_file %px\n"
 137 #ifdef CONFIG_MMU_NOTIFIER
 138                 "mmu_notifier_mm %px\n"
 139 #endif
 140 #ifdef CONFIG_NUMA_BALANCING
 141                 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
 142 #endif
 143                 "tlb_flush_pending %d\n"
 144                 "def_flags: %#lx(%pGv)\n",
 145
 146                 mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
 147 #ifdef CONFIG_MMU
 148                 mm->get_unmapped_area,
 149 #endif
 150                 mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
 151                 mm->pgd, atomic_read(&mm->mm_users),
 152                 atomic_read(&mm->mm_count),
 153                 mm_pgtables_bytes(mm),
 154                 mm->map_count,
 155                 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
 156                 mm->pinned_vm, mm->data_vm, mm->exec_vm, mm->stack_vm,
 157                 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
 158                 mm->start_brk, mm->brk, mm->start_stack,
 159                 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
 160                 mm->binfmt, mm->flags, mm->core_state,
 161 #ifdef CONFIG_AIO
 162                 mm->ioctx_table,
 163 #endif
 164 #ifdef CONFIG_MEMCG
 165                 mm->owner,
 166 #endif
 167                 mm->exe_file,
 168 #ifdef CONFIG_MMU_NOTIFIER
 169                 mm->mmu_notifier_mm,
 170 #endif
 171 #ifdef CONFIG_NUMA_BALANCING
 172                 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
 173 #endif
 174                 atomic_read(&mm->tlb_flush_pending),
 175                 mm->def_flags, &mm->def_flags
 176         );
 177 }
 178
 179 static bool page_init_poisoning __read_mostly = true;
 180
 181 static int __init setup_vm_debug(char *str)
 182 {
 183         bool __page_init_poisoning = true;
 184
 185         /*
 186          * Calling vm_debug with no arguments is equivalent to requesting
 187          * to enable all debugging options we can control.
 188          */
 189         if (*str++ != '=' || !*str)
 190                 goto out;
 191
 192         __page_init_poisoning = false;
 193         if (*str == '-')
 194                 goto out;
 195
 196         while (*str) {
 197                 switch (tolower(*str)) {
 198                 case'p':
 199                         __page_init_poisoning = true;
 200                         break;
 201                 default:
 202                         pr_err("vm_debug option '%c' unknown. skipped\n",
 203                                *str);
 204                 }
 205
 206                 str++;
 207         }
 208 out:
 209         if (page_init_poisoning && !__page_init_poisoning)
 210                 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
 211
 212         page_init_poisoning = __page_init_poisoning;
 213
 214         return 1;
 215 }
 216 __setup("vm_debug", setup_vm_debug);
 217
 218 void page_init_poison(struct page *page, size_t size)
 219 {
 220         if (page_init_poisoning)
 221                 memset(page, PAGE_POISON_PATTERN, size);
 222 }
 223 EXPORT_SYMBOL_GPL(page_init_poison);
 224 #endif          /* CONFIG_DEBUG_VM */