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- // 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/page_pinner.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, 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));
- }
- }
- 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" : "");
- 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);
- dump_page_pinner(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 */
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