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 #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 */