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_folio(struct folio *folio, struct page *page,
  55                 unsigned long pfn, unsigned long idx)
  56 {
  57         struct address_space *mapping = folio_mapping(folio);
  58         int mapcount = atomic_read(&page->_mapcount) + 1;
  59         char *type = "";
  60
  61         /* Open-code page_mapcount() to avoid looking up a stale folio */
  62         if (mapcount < 0)
  63                 mapcount = 0;
  64         if (folio_test_large(folio))
  65                 mapcount += folio_entire_mapcount(folio);
  66
  67         pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
  68                         folio_ref_count(folio), mapcount, mapping,
  69                         folio->index + idx, pfn);
  70         if (folio_test_large(folio)) {
  71                 pr_warn("head: order:%u entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
  72                                 folio_order(folio),
  73                                 folio_entire_mapcount(folio),
  74                                 folio_nr_pages_mapped(folio),
  75                                 atomic_read(&folio->_pincount));
  76         }
  77
  78 #ifdef CONFIG_MEMCG
  79         if (folio->memcg_data)
  80                 pr_warn("memcg:%lx\n", folio->memcg_data);
  81 #endif
  82         if (folio_test_ksm(folio))
  83                 type = "ksm ";
  84         else if (folio_test_anon(folio))
  85                 type = "anon ";
  86         else if (mapping)
  87                 dump_mapping(mapping);
  88         BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
  89
  90         /*
  91          * Accessing the pageblock without the zone lock. It could change to
  92          * "isolate" again in the meantime, but since we are just dumping the
  93          * state for debugging, it should be fine to accept a bit of
  94          * inaccuracy here due to racing.
  95          */
  96         pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
  97                 is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
  98         if (page_has_type(&folio->page))
  99                 pr_warn("page_type: %pGt\n", &folio->page.page_type);
 100
 101         print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
 102                         sizeof(unsigned long), page,
 103                         sizeof(struct page), false);
 104         if (folio_test_large(folio))
 105                 print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
 106                         sizeof(unsigned long), folio,
 107                         2 * sizeof(struct page), false);
 108 }
 109
 110 static void __dump_page(const struct page *page)
 111 {
 112         struct folio *foliop, folio;
 113         struct page precise;
 114         unsigned long pfn = page_to_pfn(page);
 115         unsigned long idx, nr_pages = 1;
 116         int loops = 5;
 117
 118 again:
 119         memcpy(&precise, page, sizeof(*page));
 120         foliop = page_folio(&precise);
 121         if (foliop == (struct folio *)&precise) {
 122                 idx = 0;
 123                 if (!folio_test_large(foliop))
 124                         goto dump;
 125                 foliop = (struct folio *)page;
 126         } else {
 127                 idx = folio_page_idx(foliop, page);
 128         }
 129
 130         if (idx < MAX_FOLIO_NR_PAGES) {
 131                 memcpy(&folio, foliop, 2 * sizeof(struct page));
 132                 nr_pages = folio_nr_pages(&folio);
 133                 foliop = &folio;
 134         }
 135
 136         if (idx > nr_pages) {
 137                 if (loops-- > 0)
 138                         goto again;
 139                 pr_warn("page does not match folio\n");
 140                 precise.compound_head &= ~1UL;
 141                 foliop = (struct folio *)&precise;
 142                 idx = 0;
 143         }
 144
 145 dump:
 146         __dump_folio(foliop, &precise, pfn, idx);
 147 }
 148
 149 void dump_page(const struct page *page, const char *reason)
 150 {
 151         if (PagePoisoned(page))
 152                 pr_warn("page:%p is uninitialized and poisoned", page);
 153         else
 154                 __dump_page(page);
 155         if (reason)
 156                 pr_warn("page dumped because: %s\n", reason);
 157         dump_page_owner(page);
 158 }
 159 EXPORT_SYMBOL(dump_page);
 160
 161 #ifdef CONFIG_DEBUG_VM
 162
 163 void dump_vma(const struct vm_area_struct *vma)
 164 {
 165         pr_emerg("vma %px start %px end %px mm %px\n"
 166                 "prot %lx anon_vma %px vm_ops %px\n"
 167                 "pgoff %lx file %px private_data %px\n"
 168                 "flags: %#lx(%pGv)\n",
 169                 vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
 170                 (unsigned long)pgprot_val(vma->vm_page_prot),
 171                 vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
 172                 vma->vm_file, vma->vm_private_data,
 173                 vma->vm_flags, &vma->vm_flags);
 174 }
 175 EXPORT_SYMBOL(dump_vma);
 176
 177 void dump_mm(const struct mm_struct *mm)
 178 {
 179         pr_emerg("mm %px task_size %lu\n"
 180                 "mmap_base %lu mmap_legacy_base %lu\n"
 181                 "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
 182                 "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
 183                 "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
 184                 "start_code %lx end_code %lx start_data %lx end_data %lx\n"
 185                 "start_brk %lx brk %lx start_stack %lx\n"
 186                 "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
 187                 "binfmt %px flags %lx\n"
 188 #ifdef CONFIG_AIO
 189                 "ioctx_table %px\n"
 190 #endif
 191 #ifdef CONFIG_MEMCG
 192                 "owner %px "
 193 #endif
 194                 "exe_file %px\n"
 195 #ifdef CONFIG_MMU_NOTIFIER
 196                 "notifier_subscriptions %px\n"
 197 #endif
 198 #ifdef CONFIG_NUMA_BALANCING
 199                 "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
 200 #endif
 201                 "tlb_flush_pending %d\n"
 202                 "def_flags: %#lx(%pGv)\n",
 203
 204                 mm, mm->task_size,
 205                 mm->mmap_base, mm->mmap_legacy_base,
 206                 mm->pgd, atomic_read(&mm->mm_users),
 207                 atomic_read(&mm->mm_count),
 208                 mm_pgtables_bytes(mm),
 209                 mm->map_count,
 210                 mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
 211                 (u64)atomic64_read(&mm->pinned_vm),
 212                 mm->data_vm, mm->exec_vm, mm->stack_vm,
 213                 mm->start_code, mm->end_code, mm->start_data, mm->end_data,
 214                 mm->start_brk, mm->brk, mm->start_stack,
 215                 mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
 216                 mm->binfmt, mm->flags,
 217 #ifdef CONFIG_AIO
 218                 mm->ioctx_table,
 219 #endif
 220 #ifdef CONFIG_MEMCG
 221                 mm->owner,
 222 #endif
 223                 mm->exe_file,
 224 #ifdef CONFIG_MMU_NOTIFIER
 225                 mm->notifier_subscriptions,
 226 #endif
 227 #ifdef CONFIG_NUMA_BALANCING
 228                 mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
 229 #endif
 230                 atomic_read(&mm->tlb_flush_pending),
 231                 mm->def_flags, &mm->def_flags
 232         );
 233 }
 234 EXPORT_SYMBOL(dump_mm);
 235
 236 static bool page_init_poisoning __read_mostly = true;
 237
 238 static int __init setup_vm_debug(char *str)
 239 {
 240         bool __page_init_poisoning = true;
 241
 242         /*
 243          * Calling vm_debug with no arguments is equivalent to requesting
 244          * to enable all debugging options we can control.
 245          */
 246         if (*str++ != '=' || !*str)
 247                 goto out;
 248
 249         __page_init_poisoning = false;
 250         if (*str == '-')
 251                 goto out;
 252
 253         while (*str) {
 254                 switch (tolower(*str)) {
 255                 case'p':
 256                         __page_init_poisoning = true;
 257                         break;
 258                 default:
 259                         pr_err("vm_debug option '%c' unknown. skipped\n",
 260                                *str);
 261                 }
 262
 263                 str++;
 264         }
 265 out:
 266         if (page_init_poisoning && !__page_init_poisoning)
 267                 pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
 268
 269         page_init_poisoning = __page_init_poisoning;
 270
 271         return 1;
 272 }
 273 __setup("vm_debug", setup_vm_debug);
 274
 275 void page_init_poison(struct page *page, size_t size)
 276 {
 277         if (page_init_poisoning)
 278                 memset(page, PAGE_POISON_PATTERN, size);
 279 }
 280
 281 void vma_iter_dump_tree(const struct vma_iterator *vmi)
 282 {
 283 #if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
 284         mas_dump(&vmi->mas);
 285         mt_dump(vmi->mas.tree, mt_dump_hex);
 286 #endif  /* CONFIG_DEBUG_VM_MAPLE_TREE */
 287 }
 288
 289 #endif          /* CONFIG_DEBUG_VM */