debug.c

  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#include <trace/events/migrate.h>
 20
 21/*
 22 * Define EM() and EMe() so that MIGRATE_REASON from trace/events/migrate.h can
 23 * be used to populate migrate_reason_names[].
 24 */
 25#undef EM
 26#undef EMe
 27#define EM(a, b)	b,
 28#define EMe(a, b)	b
 29
 30const char *migrate_reason_names[MR_TYPES] = {
 31	MIGRATE_REASON
 32};
 33
 34const struct trace_print_flags pageflag_names[] = {
 35	__def_pageflag_names,
 36	{0, NULL}
 37};
 38
 39const struct trace_print_flags gfpflag_names[] = {
 40	__def_gfpflag_names,
 41	{0, NULL}
 42};
 43
 44const struct trace_print_flags vmaflag_names[] = {
 45	__def_vmaflag_names,
 46	{0, NULL}
 47};
 48
 49#define DEF_PAGETYPE_NAME(_name) [PGTY_##_name - 0xf0] =  __stringify(_name)
 50
 51static const char *page_type_names[] = {
 52	DEF_PAGETYPE_NAME(slab),
 53	DEF_PAGETYPE_NAME(hugetlb),
 54	DEF_PAGETYPE_NAME(offline),
 55	DEF_PAGETYPE_NAME(guard),
 56	DEF_PAGETYPE_NAME(table),
 57	DEF_PAGETYPE_NAME(buddy),
 58	DEF_PAGETYPE_NAME(unaccepted),
 59};
 60
 61static const char *page_type_name(unsigned int page_type)
 62{
 63	unsigned i = (page_type >> 24) - 0xf0;
 64
 65	if (i >= ARRAY_SIZE(page_type_names))
 66		return "unknown";
 67	return page_type_names[i];
 68}
 69
 70static void __dump_folio(const struct folio *folio, const struct page *page,
 71		unsigned long pfn, unsigned long idx)
 72{
 73	struct address_space *mapping = folio_mapping(folio);
 74	int mapcount = atomic_read(&page->_mapcount) + 1;
 75	char *type = "";
 76
 77	if (page_mapcount_is_type(mapcount))
 78		mapcount = 0;
 79
 80	pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
 81			folio_ref_count(folio), mapcount, mapping,
 82			folio->index + idx, pfn);
 83	if (folio_test_large(folio)) {
 84		int pincount = 0;
 85
 86		if (folio_has_pincount(folio))
 87			pincount = atomic_read(&folio->_pincount);
 88
 89		pr_warn("head: order:%u mapcount:%d entire_mapcount:%d nr_pages_mapped:%d pincount:%d\n",
 90				folio_order(folio),
 91				folio_mapcount(folio),
 92				folio_entire_mapcount(folio),
 93				folio_nr_pages_mapped(folio),
 94				pincount);
 95	}
 96
 97#ifdef CONFIG_MEMCG
 98	if (folio->memcg_data)
 99		pr_warn("memcg:%lx\n", folio->memcg_data);
100#endif
101	if (folio_test_ksm(folio))
102		type = "ksm ";
103	else if (folio_test_anon(folio))
104		type = "anon ";
105	else if (mapping)
106		dump_mapping(mapping);
107	BUILD_BUG_ON(ARRAY_SIZE(pageflag_names) != __NR_PAGEFLAGS + 1);
108
109	/*
110	 * Accessing the pageblock without the zone lock. It could change to
111	 * "isolate" again in the meantime, but since we are just dumping the
112	 * state for debugging, it should be fine to accept a bit of
113	 * inaccuracy here due to racing.
114	 */
115	pr_warn("%sflags: %pGp%s\n", type, &folio->flags,
116		is_migrate_cma_folio(folio, pfn) ? " CMA" : "");
117	if (page_has_type(&folio->page))
118		pr_warn("page_type: %x(%s)\n", folio->page.page_type >> 24,
119				page_type_name(folio->page.page_type));
120
121	print_hex_dump(KERN_WARNING, "raw: ", DUMP_PREFIX_NONE, 32,
122			sizeof(unsigned long), page,
123			sizeof(struct page), false);
124	if (folio_test_large(folio))
125		print_hex_dump(KERN_WARNING, "head: ", DUMP_PREFIX_NONE, 32,
126			sizeof(unsigned long), folio,
127			2 * sizeof(struct page), false);
128}
129
130static void __dump_page(const struct page *page)
131{
132	struct page_snapshot ps;
133
134	snapshot_page(&ps, page);
135	if (!snapshot_page_is_faithful(&ps))
136		pr_warn("page does not match folio\n");
137
138	__dump_folio(&ps.folio_snapshot, &ps.page_snapshot, ps.pfn, ps.idx);
139}
140
141void dump_page(const struct page *page, const char *reason)
142{
143	if (PagePoisoned(page))
144		pr_warn("page:%p is uninitialized and poisoned\n", page);
145	else
146		__dump_page(page);
147	if (reason)
148		pr_warn("page dumped because: %s\n", reason);
149	dump_page_owner(page);
150}
151EXPORT_SYMBOL(dump_page);
152
153#ifdef CONFIG_DEBUG_VM
154
155void dump_vma(const struct vm_area_struct *vma)
156{
157	pr_emerg("vma %px start %px end %px mm %px\n"
158		"prot %lx anon_vma %px vm_ops %px\n"
159		"pgoff %lx file %px private_data %px\n"
160#ifdef CONFIG_PER_VMA_LOCK
161		"refcnt %x\n"
162#endif
163		"flags: %#lx(%pGv)\n",
164		vma, (void *)vma->vm_start, (void *)vma->vm_end, vma->vm_mm,
165		(unsigned long)pgprot_val(vma->vm_page_prot),
166		vma->anon_vma, vma->vm_ops, vma->vm_pgoff,
167		vma->vm_file, vma->vm_private_data,
168#ifdef CONFIG_PER_VMA_LOCK
169		refcount_read(&vma->vm_refcnt),
170#endif
171		vma->vm_flags, &vma->vm_flags);
172}
173EXPORT_SYMBOL(dump_vma);
174
175void dump_mm(const struct mm_struct *mm)
176{
177	pr_emerg("mm %px task_size %lu\n"
178		"mmap_base %lu mmap_legacy_base %lu\n"
179		"pgd %px mm_users %d mm_count %d pgtables_bytes %lu map_count %d\n"
180		"hiwater_rss %lx hiwater_vm %lx total_vm %lx locked_vm %lx\n"
181		"pinned_vm %llx data_vm %lx exec_vm %lx stack_vm %lx\n"
182		"start_code %lx end_code %lx start_data %lx end_data %lx\n"
183		"start_brk %lx brk %lx start_stack %lx\n"
184		"arg_start %lx arg_end %lx env_start %lx env_end %lx\n"
185		"binfmt %px flags %*pb\n"
186#ifdef CONFIG_AIO
187		"ioctx_table %px\n"
188#endif
189#ifdef CONFIG_MEMCG
190		"owner %px "
191#endif
192		"exe_file %px\n"
193#ifdef CONFIG_MMU_NOTIFIER
194		"notifier_subscriptions %px\n"
195#endif
196#ifdef CONFIG_NUMA_BALANCING
197		"numa_next_scan %lu numa_scan_offset %lu numa_scan_seq %d\n"
198#endif
199		"tlb_flush_pending %d\n"
200		"def_flags: %#lx(%pGv)\n",
201
202		mm, mm->task_size,
203		mm->mmap_base, mm->mmap_legacy_base,
204		mm->pgd, atomic_read(&mm->mm_users),
205		atomic_read(&mm->mm_count),
206		mm_pgtables_bytes(mm),
207		mm->map_count,
208		mm->hiwater_rss, mm->hiwater_vm, mm->total_vm, mm->locked_vm,
209		(u64)atomic64_read(&mm->pinned_vm),
210		mm->data_vm, mm->exec_vm, mm->stack_vm,
211		mm->start_code, mm->end_code, mm->start_data, mm->end_data,
212		mm->start_brk, mm->brk, mm->start_stack,
213		mm->arg_start, mm->arg_end, mm->env_start, mm->env_end,
214		mm->binfmt, NUM_MM_FLAG_BITS, __mm_flags_get_bitmap(mm),
215#ifdef CONFIG_AIO
216		mm->ioctx_table,
217#endif
218#ifdef CONFIG_MEMCG
219		mm->owner,
220#endif
221		mm->exe_file,
222#ifdef CONFIG_MMU_NOTIFIER
223		mm->notifier_subscriptions,
224#endif
225#ifdef CONFIG_NUMA_BALANCING
226		mm->numa_next_scan, mm->numa_scan_offset, mm->numa_scan_seq,
227#endif
228		atomic_read(&mm->tlb_flush_pending),
229		mm->def_flags, &mm->def_flags
230	);
231}
232EXPORT_SYMBOL(dump_mm);
233
234void dump_vmg(const struct vma_merge_struct *vmg, const char *reason)
235{
236	if (reason)
237		pr_warn("vmg %px dumped because: %s\n", vmg, reason);
238
239	if (!vmg) {
240		pr_warn("vmg %px state: (NULL)\n", vmg);
241		return;
242	}
243
244	pr_warn("vmg %px state: mm %px pgoff %lx\n"
245		"vmi %px [%lx,%lx)\n"
246		"prev %px middle %px next %px target %px\n"
247		"start %lx end %lx flags %lx\n"
248		"file %px anon_vma %px policy %px\n"
249		"uffd_ctx %px\n"
250		"anon_name %px\n"
251		"state %x\n"
252		"just_expand %d\n"
253		"__adjust_middle_start %d __adjust_next_start %d\n"
254		"__remove_middle %d __remove_next %d\n",
255		vmg, vmg->mm, vmg->pgoff,
256		vmg->vmi, vmg->vmi ? vma_iter_addr(vmg->vmi) : 0,
257		vmg->vmi ? vma_iter_end(vmg->vmi) : 0,
258		vmg->prev, vmg->middle, vmg->next, vmg->target,
259		vmg->start, vmg->end, vmg->vm_flags,
260		vmg->file, vmg->anon_vma, vmg->policy,
261#ifdef CONFIG_USERFAULTFD
262		vmg->uffd_ctx.ctx,
263#else
264		(void *)0,
265#endif
266		vmg->anon_name,
267		(int)vmg->state,
268		vmg->just_expand,
269		vmg->__adjust_middle_start, vmg->__adjust_next_start,
270		vmg->__remove_middle, vmg->__remove_next);
271
272	if (vmg->mm) {
273		pr_warn("vmg %px mm:\n", vmg);
274		dump_mm(vmg->mm);
275	} else {
276		pr_warn("vmg %px mm: (NULL)\n", vmg);
277	}
278
279	if (vmg->prev) {
280		pr_warn("vmg %px prev:\n", vmg);
281		dump_vma(vmg->prev);
282	} else {
283		pr_warn("vmg %px prev: (NULL)\n", vmg);
284	}
285
286	if (vmg->middle) {
287		pr_warn("vmg %px middle:\n", vmg);
288		dump_vma(vmg->middle);
289	} else {
290		pr_warn("vmg %px middle: (NULL)\n", vmg);
291	}
292
293	if (vmg->next) {
294		pr_warn("vmg %px next:\n", vmg);
295		dump_vma(vmg->next);
296	} else {
297		pr_warn("vmg %px next: (NULL)\n", vmg);
298	}
299
300#ifdef CONFIG_DEBUG_VM_MAPLE_TREE
301	if (vmg->vmi) {
302		pr_warn("vmg %px vmi:\n", vmg);
303		vma_iter_dump_tree(vmg->vmi);
304	} else {
305		pr_warn("vmg %px vmi: (NULL)\n", vmg);
306	}
307#endif
308}
309EXPORT_SYMBOL(dump_vmg);
310
311static bool page_init_poisoning __read_mostly = true;
312
313static int __init setup_vm_debug(char *str)
314{
315	bool __page_init_poisoning = true;
316
317	/*
318	 * Calling vm_debug with no arguments is equivalent to requesting
319	 * to enable all debugging options we can control.
320	 */
321	if (*str++ != '=' || !*str)
322		goto out;
323
324	__page_init_poisoning = false;
325	if (*str == '-')
326		goto out;
327
328	while (*str) {
329		switch (tolower(*str)) {
330		case 'p':
331			__page_init_poisoning = true;
332			break;
333		default:
334			pr_err("vm_debug option '%c' unknown. skipped\n",
335			       *str);
336		}
337
338		str++;
339	}
340out:
341	if (page_init_poisoning && !__page_init_poisoning)
342		pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n");
343
344	page_init_poisoning = __page_init_poisoning;
345
346	return 1;
347}
348__setup("vm_debug", setup_vm_debug);
349
350void page_init_poison(struct page *page, size_t size)
351{
352	if (page_init_poisoning)
353		memset(page, PAGE_POISON_PATTERN, size);
354}
355
356void vma_iter_dump_tree(const struct vma_iterator *vmi)
357{
358#if defined(CONFIG_DEBUG_VM_MAPLE_TREE)
359	mas_dump(&vmi->mas);
360	mt_dump(vmi->mas.tree, mt_dump_hex);
361#endif	/* CONFIG_DEBUG_VM_MAPLE_TREE */
362}
363
364#endif		/* CONFIG_DEBUG_VM */