| // 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} |
| }; |
| |
| void __dump_page(struct page *page, const char *reason) |
| { |
| struct page *head = compound_head(page); |
| struct address_space *mapping; |
| bool page_poisoned = PagePoisoned(page); |
| 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 struct page is poisoned don't access Page*() functions as that |
| * leads to recursive loop. Page*() check for poisoned pages, and calls |
| * dump_page() when detected. |
| */ |
| if (page_poisoned) { |
| pr_warn("page:%px is uninitialized and poisoned", page); |
| goto hex_only; |
| } |
| |
| if (page < head || (page >= head + MAX_ORDER_NR_PAGES)) { |
| /* Corrupt page, cannot call page_mapping */ |
| mapping = page->mapping; |
| 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); |
| |
| if (compound) |
| if (hpage_pincount_available(page)) { |
| pr_warn("page:%px refcount:%d mapcount:%d mapping:%p " |
| "index:%#lx head:%px order:%u " |
| "compound_mapcount:%d compound_pincount:%d\n", |
| page, page_ref_count(head), mapcount, |
| mapping, page_to_pgoff(page), head, |
| compound_order(head), compound_mapcount(page), |
| compound_pincount(page)); |
| } else { |
| pr_warn("page:%px refcount:%d mapcount:%d mapping:%p " |
| "index:%#lx head:%px order:%u " |
| "compound_mapcount:%d\n", |
| page, page_ref_count(head), mapcount, |
| mapping, page_to_pgoff(page), head, |
| compound_order(head), compound_mapcount(page)); |
| } |
| else |
| pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n", |
| page, page_ref_count(page), mapcount, |
| mapping, page_to_pgoff(page)); |
| if (PageKsm(page)) |
| type = "ksm "; |
| else if (PageAnon(page)) |
| type = "anon "; |
| else if (mapping) { |
| const struct inode *host; |
| const struct address_space_operations *a_ops; |
| const struct hlist_node *dentry_first; |
| const struct dentry *dentry_ptr; |
| struct dentry dentry; |
| |
| /* |
| * mapping can be invalid pointer and we don't want to crash |
| * accessing it, so probe everything depending on it carefully |
| */ |
| if (probe_kernel_read_strict(&host, &mapping->host, |
| sizeof(struct inode *)) || |
| probe_kernel_read_strict(&a_ops, &mapping->a_ops, |
| sizeof(struct address_space_operations *))) { |
| pr_warn("failed to read mapping->host or a_ops, mapping not a valid kernel address?\n"); |
| goto out_mapping; |
| } |
| |
| if (!host) { |
| pr_warn("mapping->a_ops:%ps\n", a_ops); |
| goto out_mapping; |
| } |
| |
| if (probe_kernel_read_strict(&dentry_first, |
| &host->i_dentry.first, sizeof(struct hlist_node *))) { |
| pr_warn("mapping->a_ops:%ps with invalid mapping->host inode address %px\n", |
| a_ops, host); |
| goto out_mapping; |
| } |
| |
| if (!dentry_first) { |
| pr_warn("mapping->a_ops:%ps\n", a_ops); |
| goto out_mapping; |
| } |
| |
| dentry_ptr = container_of(dentry_first, struct dentry, d_u.d_alias); |
| if (probe_kernel_read_strict(&dentry, dentry_ptr, |
| sizeof(struct dentry))) { |
| pr_warn("mapping->aops:%ps with invalid mapping->host->i_dentry.first %px\n", |
| a_ops, 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("mapping->aops:%ps dentry name:\"%pd\"\n", |
| a_ops, &dentry); |
| } |
| } |
| out_mapping: |
| BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1); |
| |
| pr_warn("%sflags: %#lx(%pGp)%s\n", type, page->flags, &page->flags, |
| page_cma ? " CMA" : ""); |
| |
| hex_only: |
| 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); |
| |
| if (reason) |
| pr_warn("page dumped because: %s\n", reason); |
| |
| #ifdef CONFIG_MEMCG |
| if (!page_poisoned && page->mem_cgroup) |
| pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup); |
| #endif |
| } |
| |
| void dump_page(struct page *page, const char *reason) |
| { |
| __dump_page(page, 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 */ |