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
 20const char *migrate_reason_names[MR_TYPES] = {
 21	"compaction",
 22	"memory_failure",
 23	"memory_hotplug",
 24	"syscall_or_cpuset",
 25	"mempolicy_mbind",
 26	"numa_misplaced",
 27	"cma",
 28};
 29
 30const struct trace_print_flags pageflag_names[] = {
 31	__def_pageflag_names,
 32	{0, NULL}
 33};
 34
 35const struct trace_print_flags gfpflag_names[] = {
 36	__def_gfpflag_names,
 37	{0, NULL}
 38};
 39
 40const struct trace_print_flags vmaflag_names[] = {
 41	__def_vmaflag_names,
 42	{0, NULL}
 43};
 44
 45void __dump_page(struct page *page, const char *reason)
 46{
 47	struct address_space *mapping;
 48	bool page_poisoned = PagePoisoned(page);
 49	int mapcount;
 50
 51	/*
 52	 * If struct page is poisoned don't access Page*() functions as that
 53	 * leads to recursive loop. Page*() check for poisoned pages, and calls
 54	 * dump_page() when detected.
 55	 */
 56	if (page_poisoned) {
 57		pr_warn("page:%px is uninitialized and poisoned", page);
 58		goto hex_only;
 59	}
 60
 61	mapping = page_mapping(page);
 62
 63	/*
 64	 * Avoid VM_BUG_ON() in page_mapcount().
 65	 * page->_mapcount space in struct page is used by sl[aou]b pages to
 66	 * encode own info.
 67	 */
 68	mapcount = PageSlab(page) ? 0 : page_mapcount(page);
 69
 70	if (PageCompound(page))
 71		pr_warn("page:%px refcount:%d mapcount:%d mapping:%px "
 72			"index:%#lx compound_mapcount: %d\n",
 73			page, page_ref_count(page), mapcount,
 74			page->mapping, page_to_pgoff(page),
 75			compound_mapcount(page));
 76	else
 77		pr_warn("page:%px refcount:%d mapcount:%d mapping:%px index:%#lx\n",
 78			page, page_ref_count(page), mapcount,
 79			page->mapping, page_to_pgoff(page));
 80	if (PageKsm(page))
 81		pr_warn("ksm flags: %#lx(%pGp)\n", page->flags, &page->flags);
 82	else if (PageAnon(page))
 83		pr_warn("anon flags: %#lx(%pGp)\n", page->flags, &page->flags);
 84	else if (mapping) {
 85		if (mapping->host && mapping->host->i_dentry.first) {
 86			struct dentry *dentry;
 87			dentry = container_of(mapping->host->i_dentry.first, struct dentry, d_u.d_alias);
 88			pr_warn("%ps name:\"%pd\"\n", mapping->a_ops, dentry);
 89		} else
 90			pr_warn("%ps\n", mapping->a_ops);
 91		pr_warn("flags: %#lx(%pGp)\n", page->flags, &page->flags);
 92	}
 93	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
 94
 95hex_only:
 96	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
 97			sizeof(unsigned long), page,
 98			sizeof(struct page), false);
 99
100	if (reason)
101		pr_warn("page dumped because: %s\n", reason);
102
103#ifdef CONFIG_MEMCG
104	if (!page_poisoned && page->mem_cgroup)
105		pr_warn("page->mem_cgroup:%px\n", page->mem_cgroup);
106#endif
107}
108
109void dump_page(struct page *page, const char *reason)
110{
111	__dump_page(page, reason);
112	dump_page_owner(page);
113}
114EXPORT_SYMBOL(dump_page);
115
116#ifdef CONFIG_DEBUG_VM
117
118void dump_vma(const struct vm_area_struct *vma)
119{
120	pr_emerg("vma %px start %px end %px\n"
121		"next %px prev %px mm %px\n"
122		"prot %lx anon_vma %px vm_ops %px\n"
123		"pgoff %lx file %px private_data %px\n"
124		"flags: %#lx(%pGv)\n",
125		vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_next,
126		vma->vm_prev, vma->vm_mm,
127		(unsigned long)pgprot_val(vma->vm_page_prot),
128		vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
129		vma->vm_file, vma->vm_private_data,
130		vma->vm_flags, &vma->vm_flags);
131}
132EXPORT_SYMBOL(dump_vma);
133
134void dump_mm(const struct mm_struct *mm)
135{
136	pr_emerg("mm %px mmap %px seqnum %llu task_size %lu\n"
137#ifdef CONFIG_MMU
138		"get_unmapped_area %px\n"
139#endif
140		"mmap_base %lu mmap_legacy_base %lu highest_vm_end %lu\n"
141		"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
142		"hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
143		"pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
144		"start_code %lx end_code %lx start_data %lx end_data %lx\n"
145		"start_brk %lx brk %lx start_stack %lx\n"
146		"arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
147		"binfmt %px flags %lx core_state %px\n"
148#ifdef CONFIG_AIO
149		"ioctx_table %px\n"
150#endif
151#ifdef CONFIG_MEMCG
152		"owner %px "
153#endif
154		"exe_file %px\n"
155#ifdef CONFIG_MMU_NOTIFIER
156		"mmu_notifier_mm %px\n"
157#endif
158#ifdef CONFIG_NUMA_BALANCING
159		"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
160#endif
161		"tlb_flush_pending %d\n"
162		"def_flags: %#lx(%pGv)\n",
163
164		mm, mm->mmap, (long long) mm->vmacache_seqnum, mm->task_size,
165#ifdef CONFIG_MMU
166		mm->get_unmapped_area,
167#endif
168		mm->mmap_base, mm->mmap_legacy_base, mm->highest_vm_end,
169		mm->pgd, atomic_read(&mm->mm_users),
170		atomic_read(&mm->mm_count),
171		mm_pgtables_bytes(mm),
172		mm->map_count,
173		mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
174		(u64)atomic64_read(&mm->pinned_vm),
175		mm->data_vm, mm->exec_vm, mm->stack_vm,
176		mm->start_code, mm->end_code, mm->start_data, mm->end_data,
177		mm->start_brk, mm->brk, mm->start_stack,
178		mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
179		mm->binfmt, mm->flags, mm->core_state,
180#ifdef CONFIG_AIO
181		mm->ioctx_table,
182#endif
183#ifdef CONFIG_MEMCG
184		mm->owner,
185#endif
186		mm->exe_file,
187#ifdef CONFIG_MMU_NOTIFIER
188		mm->mmu_notifier_mm,
189#endif
190#ifdef CONFIG_NUMA_BALANCING
191		mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
192#endif
193		atomic_read(&mm->tlb_flush_pending),
194		mm->def_flags, &mm->def_flags
195	);
196}
197
198static bool page_init_poisoning __read_mostly = true;
199
200static int __init setup_vm_debug(char *str)
201{
202	bool __page_init_poisoning = true;
203
204	/*
205	 * Calling vm_debug with no arguments is equivalent to requesting
206	 * to enable all debugging options we can control.
207	 */
208	if (*str++ != '=' || !*str)
209		goto out;
210
211	__page_init_poisoning = false;
212	if (*str == '-')
213		goto out;
214
215	while (*str) {
216		switch (tolower(*str)) {
217		case'p':
218			__page_init_poisoning = true;
219			break;
220		default:
221			pr_err("vm_debug option '%c' unknown. skipped\n",
222			       *str);
223		}
224
225		str++;
226	}
227out:
228	if (page_init_poisoning && !__page_init_poisoning)
229		pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
230
231	page_init_poisoning = __page_init_poisoning;
232
233	return 1;
234}
235__setup("vm_debug", setup_vm_debug);
236
237void page_init_poison(struct page *page, size_t size)
238{
239	if (page_init_poisoning)
240		memset(page, PAGE_POISON_PATTERN, size);
241}
242EXPORT_SYMBOL_GPL(page_init_poison);
243#endif		/* CONFIG_DEBUG_VM */