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