the-tree/mm/debug.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 /*
0003  * mm/debug.c
0004  *
0005  * mm/ specific debug routines.
0006  *
0007  */
0008
0009 #include <linux/kernel.h>
0010 #include <linux/mm.h>
0011 #include <linux/trace_events.h>
0012 #include <linux/memcontrol.h>
0013 #include <trace/events/mmflags.h>
0014 #include <linux/migrate.h>
0015 #include <linux/page_owner.h>
0016 #include <linux/ctype.h>
0017
0018 #include "internal.h"
0019 #include <trace/events/migrate.h>
0020
0021 /*
0022  * Define EM() and EMe() so that MIGRATE_REASON from trace/events/migrate.h can
0023  * be used to populate migrate_reason_names[].
0024  */
0025 #undef EM
0026 #undef EMe
0027 #define EM(a, b)    b,
0028 #define EMe(a, b)   b
0029
0030 const char *migrate_reason_names[MR_TYPES] = {
0031     MIGRATE_REASON
0032 };
0033
0034 const struct trace_print_flags pageflag_names[] = {
0035     __def_pageflag_names,
0036     {0, NULL}
0037 };
0038
0039 const struct trace_print_flags gfpflag_names[] = {
0040     __def_gfpflag_names,
0041     {0, NULL}
0042 };
0043
0044 const struct trace_print_flags vmaflag_names[] = {
0045     __def_vmaflag_names,
0046     {0, NULL}
0047 };
0048
0049 static void __dump_page(struct page *page)
0050 {
0051     struct folio *folio = page_folio(page);
0052     struct page *head = &folio->page;
0053     struct address_space *mapping;
0054     bool compound = PageCompound(page);
0055     /*
0056      * Accessing the pageblock without the zone lock. It could change to
0057      * "isolate" again in the meantime, but since we are just dumping the
0058      * state for debugging, it should be fine to accept a bit of
0059      * inaccuracy here due to racing.
0060      */
0061     bool page_cma = is_migrate_cma_page(page);
0062     int mapcount;
0063     char *type = "";
0064
0065     if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) {
0066         /*
0067          * Corrupt page, so we cannot call page_mapping. Instead, do a
0068          * safe subset of the steps that page_mapping() does. Caution:
0069          * this will be misleading for tail pages, PageSwapCache pages,
0070          * and potentially other situations. (See the page_mapping()
0071          * implementation for what's missing here.)
0072          */
0073         unsigned long tmp = (unsigned long)page->mapping;
0074
0075         if (tmp & PAGE_MAPPING_ANON)
0076             mapping = NULL;
0077         else
0078             mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS);
0079         head = page;
0080         folio = (struct folio *)page;
0081         compound = false;
0082     } else {
0083         mapping = page_mapping(page);
0084     }
0085
0086     /*
0087      * Avoid VM_BUG_ON() in page_mapcount().
0088      * page->_mapcount space in struct page is used by sl[aou]b pages to
0089      * encode own info.
0090      */
0091     mapcount = PageSlab(head) ? 0 : page_mapcount(page);
0092
0093     pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
0094             page, page_ref_count(head), mapcount, mapping,
0095             page_to_pgoff(page), page_to_pfn(page));
0096     if (compound) {
0097         pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n",
0098                 head, compound_order(head),
0099                 folio_entire_mapcount(folio),
0100                 head_compound_pincount(head));
0101     }
0102
0103 #ifdef CONFIG_MEMCG
0104     if (head->memcg_data)
0105         pr_warn("memcg:%lx\n", head->memcg_data);
0106 #endif
0107     if (PageKsm(page))
0108         type = "ksm ";
0109     else if (PageAnon(page))
0110         type = "anon ";
0111     else if (mapping)
0112         dump_mapping(mapping);
0113     BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
0114
0115     pr_warn("%sflags: %pGp%s\n", type, &head->flags,
0116         page_cma ? " CMA" : "");
0117     print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
0118             sizeof(unsigned long), page,
0119             sizeof(struct page), false);
0120     if (head != page)
0121         print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
0122             sizeof(unsigned long), head,
0123             sizeof(struct page), false);
0124 }
0125
0126 void dump_page(struct page *page, const char *reason)
0127 {
0128     if (PagePoisoned(page))
0129         pr_warn("page:%p is uninitialized and poisoned", page);
0130     else
0131         __dump_page(page);
0132     if (reason)
0133         pr_warn("page dumped because: %s\n", reason);
0134     dump_page_owner(page);
0135 }
0136 EXPORT_SYMBOL(dump_page);
0137
0138 #ifdef CONFIG_DEBUG_VM
0139
0140 void dump_vma(const struct vm_area_struct *vma)
0141 {
0142     pr_emerg("vma %px start %px end %px\n"
0143         "next %px prev %px mm %px\n"
0144         "prot %lx anon_vma %px vm_ops %px\n"
0145         "pgoff %lx file %px private_data %px\n"
0146         "flags: %#lx(%pGv)\n",
0147         vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
0148         vma->vm_prev, vma->vm_mm,
0149         (unsigned long)pgprot_val(vma->vm_page_prot),
0150         vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
0151         vma->vm_file, vma->vm_private_data,
0152         vma->vm_flags, &vma->vm_flags);
0153 }
0154 EXPORT_SYMBOL(dump_vma);
0155
0156 void dump_mm(const struct mm_struct *mm)
0157 {
0158     pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
0159 #ifdef CONFIG_MMU
0160         "get_unmapped_area %px\n"
0161 #endif
0162         "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
0163         "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
0164         "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
0165         "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
0166         "start_code %lx end_code %lx start_data %lx end_data %lx\n"
0167         "start_brk %lx brk %lx start_stack %lx\n"
0168         "arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
0169         "binfmt %px flags %lx\n"
0170 #ifdef CONFIG_AIO
0171         "ioctx_table %px\n"
0172 #endif
0173 #ifdef CONFIG_MEMCG
0174         "owner %px "
0175 #endif
0176         "exe_file %px\n"
0177 #ifdef CONFIG_MMU_NOTIFIER
0178         "notifier_subscriptions %px\n"
0179 #endif
0180 #ifdef CONFIG_NUMA_BALANCING
0181         "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
0182 #endif
0183         "tlb_flush_pending %d\n"
0184         "def_flags: %#lx(%pGv)\n",
0185
0186         mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
0187 #ifdef CONFIG_MMU
0188         mm->get_unmapped_area,
0189 #endif
0190         mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
0191         mm->pgd, atomic_read(&mm->mm_users),
0192         atomic_read(&mm->mm_count),
0193         mm_pgtables_bytes(mm),
0194         mm->map_count,
0195         mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
0196         (u64)atomic64_read(&mm->pinned_vm),
0197         mm->data_vm, mm->exec_vm, mm->stack_vm,
0198         mm->start_code, mm->end_code, mm->start_data, mm->end_data,
0199         mm->start_brk, mm->brk, mm->start_stack,
0200         mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
0201         mm->binfmt, mm->flags,
0202 #ifdef CONFIG_AIO
0203         mm->ioctx_table,
0204 #endif
0205 #ifdef CONFIG_MEMCG
0206         mm->owner,
0207 #endif
0208         mm->exe_file,
0209 #ifdef CONFIG_MMU_NOTIFIER
0210         mm->notifier_subscriptions,
0211 #endif
0212 #ifdef CONFIG_NUMA_BALANCING
0213         mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
0214 #endif
0215         atomic_read(&mm->tlb_flush_pending),
0216         mm->def_flags, &mm->def_flags
0217     );
0218 }
0219
0220 static bool page_init_poisoning __read_mostly = true;
0221
0222 static int __init setup_vm_debug(char *str)
0223 {
0224     bool __page_init_poisoning = true;
0225
0226     /*
0227      * Calling vm_debug with no arguments is equivalent to requesting
0228      * to enable all debugging options we can control.
0229      */
0230     if (*str++ != '=' || !*str)
0231         goto out;
0232
0233     __page_init_poisoning = false;
0234     if (*str == '-')
0235         goto out;
0236
0237     while (*str) {
0238         switch (tolower(*str)) {
0239         case'p':
0240             __page_init_poisoning = true;
0241             break;
0242         default:
0243             pr_err("vm_debug option '%c' unknown. skipped\n",
0244                    *str);
0245         }
0246
0247         str++;
0248     }
0249 out:
0250     if (page_init_poisoning && !__page_init_poisoning)
0251         pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
0252
0253     page_init_poisoning = __page_init_poisoning;
0254
0255     return 1;
0256 }
0257 __setup("vm_debug", setup_vm_debug);
0258
0259 void page_init_poison(struct page *page, size_t size)
0260 {
0261     if (page_init_poisoning)
0262         memset(page, PAGE_POISON_PATTERN, size);
0263 }
0264 #endif      /* CONFIG_DEBUG_VM */