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 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 */