// SPDX-License-Identifier: GPL-2.0 /* * mm/debug.c * * mm/ specific debug routines. * */ #include <linux/kernel.h> #include <linux/mm.h> #include <linux/trace_events.h> #include <linux/memcontrol.h> #include <trace/events/mmflags.h> #include <linux/migrate.h> #include <linux/page_owner.h> #include <linux/ctype.h> #include "internal.h" const char *migrate_reason_names[MR_TYPES] = { "compaction", "memory_failure", "memory_hotplug", "syscall_or_cpuset", "mempolicy_mbind", "numa_misplaced", "cma", }; const struct trace_print_flags pageflag_names[] = { __def_pageflag_names, {0, NULL} }; const struct trace_print_flags gfpflag_names[] = { __def_gfpflag_names, {0, NULL} }; const struct trace_print_flags vmaflag_names[] = { __def_vmaflag_names, {0, NULL} }; static void __dump_page(struct page *page) { struct page *head = compound_head(page); struct address_space *mapping; bool compound = PageCompound(page); /* * Accessing the pageblock without the zone lock. It could change to * "isolate" again in the meantime, but since we are just dumping the * state for debugging, it should be fine to accept a bit of * inaccuracy here due to racing. */ bool page_cma = is_migrate_cma_page(page); int mapcount; char *type = ""; if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) { /* * Corrupt page, so we cannot call page_mapping. Instead, do a * safe subset of the steps that page_mapping() does. Caution: * this will be misleading for tail pages, PageSwapCache pages, * and potentially other situations. (See the page_mapping() * implementation for what's missing here.) */ unsigned long tmp = (unsigned long)page->mapping; if (tmp & PAGE_MAPPING_ANON) mapping = NULL; else mapping = (void *)(tmp & ~PAGE_MAPPING_FLAGS); head = page; compound = false; } else { mapping = page_mapping(page); } /* * Avoid VM_BUG_ON() in page_mapcount(). * page->_mapcount space in struct page is used by sl[aou]b pages to * encode own info. */ mapcount = PageSlab(head) ? 0 : page_mapcount(page); pr_warn("page:%p refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n", page, page_ref_count(head), mapcount, mapping, page_to_pgoff(page), page_to_pfn(page)); if (compound) { if (hpage_pincount_available(page)) { pr_warn("head:%p order:%u compound_mapcount:%d compound_pincount:%d\n", head, compound_order(head), head_compound_mapcount(head), head_compound_pincount(head)); } else { pr_warn("head:%p order:%u compound_mapcount:%d\n", head, compound_order(head), head_compound_mapcount(head)); } } #ifdef CONFIG_MEMCG if (head->memcg_data) pr_warn("memcg:%lx\n", head->memcg_data); #endif if (PageKsm(page)) type = "ksm "; else if (PageAnon(page)) type = "anon "; else if (mapping) { struct inode *host; const struct address_space_operations *a_ops; struct hlist_node *dentry_first; struct dentry *dentry_ptr; struct dentry dentry; unsigned long ino; /* * mapping can be invalid pointer and we don't want to crash * accessing it, so probe everything depending on it carefully */ if (get_kernel_nofault(host, &mapping->host) || get_kernel_nofault(a_ops, &mapping->a_ops)) { pr_warn("failed to read mapping contents, not a valid kernel address?\n"); goto out_mapping; } if (!host) { pr_warn("aops:%ps\n", a_ops); goto out_mapping; } if (get_kernel_nofault(dentry_first, &host->i_dentry.first) || get_kernel_nofault(ino, &host->i_ino)) { pr_warn("aops:%ps with invalid host inode %px\n", a_ops, host); goto out_mapping; } if (!dentry_first) { pr_warn("aops:%ps ino:%lx\n", a_ops, ino); goto out_mapping; } dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias); if (get_kernel_nofault(dentry, dentry_ptr)) { pr_warn("aops:%ps ino:%lx with invalid dentry %px\n", a_ops, ino, dentry_ptr); } else { /* * if dentry is corrupted, the %pd handler may still * crash, but it's unlikely that we reach here with a * corrupted struct page */ pr_warn("aops:%ps ino:%lx dentry name:\"%pd\"\n", a_ops, ino, &dentry); } } out_mapping: BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); pr_warn("%sflags: %#lx(%pGp)%s\n", type, head->flags, &head->flags, page_cma ? " CMA" : ""); print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32, sizeof(unsigned long), page, sizeof(struct page), false); if (head != page) print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32, sizeof(unsigned long), head, sizeof(struct page), false); } void dump_page(struct page *page, const char *reason) { if (PagePoisoned(page)) pr_warn("page:%p is uninitialized and poisoned", page); else __dump_page(page); if (reason) pr_warn("page dumped because: %s\n", reason); dump_page_owner(page); } EXPORT_SYMBOL(dump_page); #ifdef CONFIG_DEBUG_VM void dump_vma(const struct vm_area_struct *vma) { pr_emerg("vma %px start %px end %px\n" "next %px prev %px mm %px\n" "prot %lx anon_vma %px vm_ops %px\n" "pgoff %lx file %px private_data %px\n" "flags: %#lx(%pGv)\n", vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next, vma->vm_prev, vma->vm_mm, (unsigned long)pgprot_val(vma->vm_page_prot), vma->anon_vma, vma->vm_ops, vma->vm_pgoff, vma->vm_file, vma->vm_private_data, vma->vm_flags, &vma->vm_flags); } EXPORT_SYMBOL(dump_vma); void dump_mm(const struct mm_struct *mm) { pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n" #ifdef CONFIG_MMU "get_unmapped_area %px\n" #endif "mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n" "pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n" "hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n" "pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n" "start_code %lx end_code %lx start_data %lx end_data %lx\n" "start_brk %lx brk %lx start_stack %lx\n" "arg_start %lx arg_end %lx env_start %lx env_end %lx\n" "binfmt %px flags %lx core_state %px\n" #ifdef CONFIG_AIO "ioctx_table %px\n" #endif #ifdef CONFIG_MEMCG "owner %px " #endif "exe_file %px\n" #ifdef CONFIG_MMU_NOTIFIER "notifier_subscriptions %px\n" #endif #ifdef CONFIG_NUMA_BALANCING "numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n" #endif "tlb_flush_pending %d\n" "def_flags: %#lx(%pGv)\n", mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size, #ifdef CONFIG_MMU mm->get_unmapped_area, #endif mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end, mm->pgd, atomic_read(&mm->mm_users), atomic_read(&mm->mm_count), mm_pgtables_bytes(mm), mm->map_count, mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm, (u64)atomic64_read(&mm->pinned_vm), mm->data_vm, mm->exec_vm, mm->stack_vm, mm->start_code, mm->end_code, mm->start_data, mm->end_data, mm->start_brk, mm->brk, mm->start_stack, mm->arg_start, mm->arg_end, mm->env_start, mm->env_end, mm->binfmt, mm->flags, mm->core_state, #ifdef CONFIG_AIO mm->ioctx_table, #endif #ifdef CONFIG_MEMCG mm->owner, #endif mm->exe_file, #ifdef CONFIG_MMU_NOTIFIER mm->notifier_subscriptions, #endif #ifdef CONFIG_NUMA_BALANCING mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq, #endif atomic_read(&mm->tlb_flush_pending), mm->def_flags, &mm->def_flags ); } static bool page_init_poisoning __read_mostly = true; static int __init setup_vm_debug(char *str) { bool __page_init_poisoning = true; /* * Calling vm_debug with no arguments is equivalent to requesting * to enable all debugging options we can control. */ if (*str++ != '=' || !*str) goto out; __page_init_poisoning = false; if (*str == '-') goto out; while (*str) { switch (tolower(*str)) { case'p': __page_init_poisoning = true; break; default: pr_err("vm_debug option '%c' unknown. skipped\n", *str); } str++; } out: if (page_init_poisoning && !__page_init_poisoning) pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n"); page_init_poisoning = __page_init_poisoning; return 1; } __setup("vm_debug", setup_vm_debug); void page_init_poison(struct page *page, size_t size) { if (page_init_poisoning) memset(page, PAGE_POISON_PATTERN, size); } EXPORT_SYMBOL_GPL(page_init_poison); #endif /* CONFIG_DEBUG_VM */