1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 2008, 2009 Intel Corporation
4 * Authors: Andi Kleen, Fengguang Wu
6 * High level machine check handler. Handles pages reported by the
7 * hardware as being corrupted usually due to a multi-bit ECC memory or cache
10 * In addition there is a "soft offline" entry point that allows stop using
11 * not-yet-corrupted-by-suspicious pages without killing anything.
13 * Handles page cache pages in various states. The tricky part
14 * here is that we can access any page asynchronously in respect to
15 * other VM users, because memory failures could happen anytime and
16 * anywhere. This could violate some of their assumptions. This is why
17 * this code has to be extremely careful. Generally it tries to use
18 * normal locking rules, as in get the standard locks, even if that means
19 * the error handling takes potentially a long time.
21 * It can be very tempting to add handling for obscure cases here.
22 * In general any code for handling new cases should only be added iff:
23 * - You know how to test it.
24 * - You have a test that can be added to mce-test
25 * https://git.kernel.org/cgit/utils/cpu/mce/mce-test.git/
26 * - The case actually shows up as a frequent (top 10) page state in
27 * tools/mm/page-types when running a real workload.
29 * There are several operations here with exponential complexity because
30 * of unsuitable VM data structures. For example the operation to map back
31 * from RMAP chains to processes has to walk the complete process list and
32 * has non linear complexity with the number. But since memory corruptions
33 * are rare we hope to get away with this. This avoids impacting the core
37 #define pr_fmt(fmt) "Memory failure: " fmt
39 #include <linux/kernel.h>
41 #include <linux/page-flags.h>
42 #include <linux/sched/signal.h>
43 #include <linux/sched/task.h>
44 #include <linux/dax.h>
45 #include <linux/ksm.h>
46 #include <linux/rmap.h>
47 #include <linux/export.h>
48 #include <linux/pagemap.h>
49 #include <linux/swap.h>
50 #include <linux/backing-dev.h>
51 #include <linux/migrate.h>
52 #include <linux/slab.h>
53 #include <linux/swapops.h>
54 #include <linux/hugetlb.h>
55 #include <linux/memory_hotplug.h>
56 #include <linux/mm_inline.h>
57 #include <linux/memremap.h>
58 #include <linux/kfifo.h>
59 #include <linux/ratelimit.h>
60 #include <linux/pagewalk.h>
61 #include <linux/shmem_fs.h>
62 #include <linux/sysctl.h>
65 #include "ras/ras_event.h"
67 static int sysctl_memory_failure_early_kill __read_mostly
;
69 static int sysctl_memory_failure_recovery __read_mostly
= 1;
71 atomic_long_t num_poisoned_pages __read_mostly
= ATOMIC_LONG_INIT(0);
73 static bool hw_memory_failure __read_mostly
= false;
75 static DEFINE_MUTEX(mf_mutex
);
77 void num_poisoned_pages_inc(unsigned long pfn
)
79 atomic_long_inc(&num_poisoned_pages
);
80 memblk_nr_poison_inc(pfn
);
83 void num_poisoned_pages_sub(unsigned long pfn
, long i
)
85 atomic_long_sub(i
, &num_poisoned_pages
);
87 memblk_nr_poison_sub(pfn
, i
);
91 * MF_ATTR_RO - Create sysfs entry for each memory failure statistics.
92 * @_name: name of the file in the per NUMA sysfs directory.
94 #define MF_ATTR_RO(_name) \
95 static ssize_t _name##_show(struct device *dev, \
96 struct device_attribute *attr, \
99 struct memory_failure_stats *mf_stats = \
100 &NODE_DATA(dev->id)->mf_stats; \
101 return sprintf(buf, "%lu\n", mf_stats->_name); \
103 static DEVICE_ATTR_RO(_name)
109 MF_ATTR_RO(recovered
);
111 static struct attribute
*memory_failure_attr
[] = {
112 &dev_attr_total
.attr
,
113 &dev_attr_ignored
.attr
,
114 &dev_attr_failed
.attr
,
115 &dev_attr_delayed
.attr
,
116 &dev_attr_recovered
.attr
,
120 const struct attribute_group memory_failure_attr_group
= {
121 .name
= "memory_failure",
122 .attrs
= memory_failure_attr
,
125 static struct ctl_table memory_failure_table
[] = {
127 .procname
= "memory_failure_early_kill",
128 .data
= &sysctl_memory_failure_early_kill
,
129 .maxlen
= sizeof(sysctl_memory_failure_early_kill
),
131 .proc_handler
= proc_dointvec_minmax
,
132 .extra1
= SYSCTL_ZERO
,
133 .extra2
= SYSCTL_ONE
,
136 .procname
= "memory_failure_recovery",
137 .data
= &sysctl_memory_failure_recovery
,
138 .maxlen
= sizeof(sysctl_memory_failure_recovery
),
140 .proc_handler
= proc_dointvec_minmax
,
141 .extra1
= SYSCTL_ZERO
,
142 .extra2
= SYSCTL_ONE
,
149 * 1: the page is dissolved (if needed) and taken off from buddy,
150 * 0: the page is dissolved (if needed) and not taken off from buddy,
151 * < 0: failed to dissolve.
153 static int __page_handle_poison(struct page
*page
)
157 zone_pcp_disable(page_zone(page
));
158 ret
= dissolve_free_huge_page(page
);
160 ret
= take_page_off_buddy(page
);
161 zone_pcp_enable(page_zone(page
));
166 static bool page_handle_poison(struct page
*page
, bool hugepage_or_freepage
, bool release
)
168 if (hugepage_or_freepage
) {
170 * Doing this check for free pages is also fine since dissolve_free_huge_page
171 * returns 0 for non-hugetlb pages as well.
173 if (__page_handle_poison(page
) <= 0)
175 * We could fail to take off the target page from buddy
176 * for example due to racy page allocation, but that's
177 * acceptable because soft-offlined page is not broken
178 * and if someone really want to use it, they should
184 SetPageHWPoison(page
);
188 num_poisoned_pages_inc(page_to_pfn(page
));
193 #if IS_ENABLED(CONFIG_HWPOISON_INJECT)
195 u32 hwpoison_filter_enable
= 0;
196 u32 hwpoison_filter_dev_major
= ~0U;
197 u32 hwpoison_filter_dev_minor
= ~0U;
198 u64 hwpoison_filter_flags_mask
;
199 u64 hwpoison_filter_flags_value
;
200 EXPORT_SYMBOL_GPL(hwpoison_filter_enable
);
201 EXPORT_SYMBOL_GPL(hwpoison_filter_dev_major
);
202 EXPORT_SYMBOL_GPL(hwpoison_filter_dev_minor
);
203 EXPORT_SYMBOL_GPL(hwpoison_filter_flags_mask
);
204 EXPORT_SYMBOL_GPL(hwpoison_filter_flags_value
);
206 static int hwpoison_filter_dev(struct page
*p
)
208 struct address_space
*mapping
;
211 if (hwpoison_filter_dev_major
== ~0U &&
212 hwpoison_filter_dev_minor
== ~0U)
215 mapping
= page_mapping(p
);
216 if (mapping
== NULL
|| mapping
->host
== NULL
)
219 dev
= mapping
->host
->i_sb
->s_dev
;
220 if (hwpoison_filter_dev_major
!= ~0U &&
221 hwpoison_filter_dev_major
!= MAJOR(dev
))
223 if (hwpoison_filter_dev_minor
!= ~0U &&
224 hwpoison_filter_dev_minor
!= MINOR(dev
))
230 static int hwpoison_filter_flags(struct page
*p
)
232 if (!hwpoison_filter_flags_mask
)
235 if ((stable_page_flags(p
) & hwpoison_filter_flags_mask
) ==
236 hwpoison_filter_flags_value
)
243 * This allows stress tests to limit test scope to a collection of tasks
244 * by putting them under some memcg. This prevents killing unrelated/important
245 * processes such as /sbin/init. Note that the target task may share clean
246 * pages with init (eg. libc text), which is harmless. If the target task
247 * share _dirty_ pages with another task B, the test scheme must make sure B
248 * is also included in the memcg. At last, due to race conditions this filter
249 * can only guarantee that the page either belongs to the memcg tasks, or is
253 u64 hwpoison_filter_memcg
;
254 EXPORT_SYMBOL_GPL(hwpoison_filter_memcg
);
255 static int hwpoison_filter_task(struct page
*p
)
257 if (!hwpoison_filter_memcg
)
260 if (page_cgroup_ino(p
) != hwpoison_filter_memcg
)
266 static int hwpoison_filter_task(struct page
*p
) { return 0; }
269 int hwpoison_filter(struct page
*p
)
271 if (!hwpoison_filter_enable
)
274 if (hwpoison_filter_dev(p
))
277 if (hwpoison_filter_flags(p
))
280 if (hwpoison_filter_task(p
))
286 int hwpoison_filter(struct page
*p
)
292 EXPORT_SYMBOL_GPL(hwpoison_filter
);
295 * Kill all processes that have a poisoned page mapped and then isolate
299 * Find all processes having the page mapped and kill them.
300 * But we keep a page reference around so that the page is not
301 * actually freed yet.
302 * Then stash the page away
304 * There's no convenient way to get back to mapped processes
305 * from the VMAs. So do a brute-force search over all
308 * Remember that machine checks are not common (or rather
309 * if they are common you have other problems), so this shouldn't
310 * be a performance issue.
312 * Also there are some races possible while we get from the
313 * error detection to actually handle it.
318 struct task_struct
*tsk
;
324 * Send all the processes who have the page mapped a signal.
325 * ``action optional'' if they are not immediately affected by the error
326 * ``action required'' if error happened in current execution context
328 static int kill_proc(struct to_kill
*tk
, unsigned long pfn
, int flags
)
330 struct task_struct
*t
= tk
->tsk
;
331 short addr_lsb
= tk
->size_shift
;
334 pr_err("%#lx: Sending SIGBUS to %s:%d due to hardware memory corruption\n",
335 pfn
, t
->comm
, t
->pid
);
337 if ((flags
& MF_ACTION_REQUIRED
) && (t
== current
))
338 ret
= force_sig_mceerr(BUS_MCEERR_AR
,
339 (void __user
*)tk
->addr
, addr_lsb
);
342 * Signal other processes sharing the page if they have
344 * Don't use force here, it's convenient if the signal
345 * can be temporarily blocked.
346 * This could cause a loop when the user sets SIGBUS
347 * to SIG_IGN, but hopefully no one will do that?
349 ret
= send_sig_mceerr(BUS_MCEERR_AO
, (void __user
*)tk
->addr
,
352 pr_info("Error sending signal to %s:%d: %d\n",
353 t
->comm
, t
->pid
, ret
);
358 * Unknown page type encountered. Try to check whether it can turn PageLRU by
361 void shake_page(struct page
*p
)
366 * TODO: Could shrink slab caches here if a lightweight range-based
367 * shrinker will be available.
374 EXPORT_SYMBOL_GPL(shake_page
);
376 static unsigned long dev_pagemap_mapping_shift(struct vm_area_struct
*vma
,
377 unsigned long address
)
379 unsigned long ret
= 0;
387 VM_BUG_ON_VMA(address
== -EFAULT
, vma
);
388 pgd
= pgd_offset(vma
->vm_mm
, address
);
389 if (!pgd_present(*pgd
))
391 p4d
= p4d_offset(pgd
, address
);
392 if (!p4d_present(*p4d
))
394 pud
= pud_offset(p4d
, address
);
395 if (!pud_present(*pud
))
397 if (pud_devmap(*pud
))
399 pmd
= pmd_offset(pud
, address
);
400 if (!pmd_present(*pmd
))
402 if (pmd_devmap(*pmd
))
404 pte
= pte_offset_map(pmd
, address
);
407 ptent
= ptep_get(pte
);
408 if (pte_present(ptent
) && pte_devmap(ptent
))
415 * Failure handling: if we can't find or can't kill a process there's
416 * not much we can do. We just print a message and ignore otherwise.
419 #define FSDAX_INVALID_PGOFF ULONG_MAX
422 * Schedule a process for later kill.
423 * Uses GFP_ATOMIC allocations to avoid potential recursions in the VM.
425 * Note: @fsdax_pgoff is used only when @p is a fsdax page and a
426 * filesystem with a memory failure handler has claimed the
427 * memory_failure event. In all other cases, page->index and
428 * page->mapping are sufficient for mapping the page back to its
429 * corresponding user virtual address.
431 static void __add_to_kill(struct task_struct
*tsk
, struct page
*p
,
432 struct vm_area_struct
*vma
, struct list_head
*to_kill
,
433 unsigned long ksm_addr
, pgoff_t fsdax_pgoff
)
437 tk
= kmalloc(sizeof(struct to_kill
), GFP_ATOMIC
);
439 pr_err("Out of memory while machine check handling\n");
443 tk
->addr
= ksm_addr
? ksm_addr
: page_address_in_vma(p
, vma
);
444 if (is_zone_device_page(p
)) {
445 if (fsdax_pgoff
!= FSDAX_INVALID_PGOFF
)
446 tk
->addr
= vma_pgoff_address(fsdax_pgoff
, 1, vma
);
447 tk
->size_shift
= dev_pagemap_mapping_shift(vma
, tk
->addr
);
449 tk
->size_shift
= page_shift(compound_head(p
));
452 * Send SIGKILL if "tk->addr == -EFAULT". Also, as
453 * "tk->size_shift" is always non-zero for !is_zone_device_page(),
454 * so "tk->size_shift == 0" effectively checks no mapping on
455 * ZONE_DEVICE. Indeed, when a devdax page is mmapped N times
456 * to a process' address space, it's possible not all N VMAs
457 * contain mappings for the page, but at least one VMA does.
458 * Only deliver SIGBUS with payload derived from the VMA that
459 * has a mapping for the page.
461 if (tk
->addr
== -EFAULT
) {
462 pr_info("Unable to find user space address %lx in %s\n",
463 page_to_pfn(p
), tsk
->comm
);
464 } else if (tk
->size_shift
== 0) {
469 get_task_struct(tsk
);
471 list_add_tail(&tk
->nd
, to_kill
);
474 static void add_to_kill_anon_file(struct task_struct
*tsk
, struct page
*p
,
475 struct vm_area_struct
*vma
,
476 struct list_head
*to_kill
)
478 __add_to_kill(tsk
, p
, vma
, to_kill
, 0, FSDAX_INVALID_PGOFF
);
482 static bool task_in_to_kill_list(struct list_head
*to_kill
,
483 struct task_struct
*tsk
)
485 struct to_kill
*tk
, *next
;
487 list_for_each_entry_safe(tk
, next
, to_kill
, nd
) {
494 void add_to_kill_ksm(struct task_struct
*tsk
, struct page
*p
,
495 struct vm_area_struct
*vma
, struct list_head
*to_kill
,
496 unsigned long ksm_addr
)
498 if (!task_in_to_kill_list(to_kill
, tsk
))
499 __add_to_kill(tsk
, p
, vma
, to_kill
, ksm_addr
, FSDAX_INVALID_PGOFF
);
503 * Kill the processes that have been collected earlier.
505 * Only do anything when FORCEKILL is set, otherwise just free the
506 * list (this is used for clean pages which do not need killing)
507 * Also when FAIL is set do a force kill because something went
510 static void kill_procs(struct list_head
*to_kill
, int forcekill
, bool fail
,
511 unsigned long pfn
, int flags
)
513 struct to_kill
*tk
, *next
;
515 list_for_each_entry_safe(tk
, next
, to_kill
, nd
) {
518 * In case something went wrong with munmapping
519 * make sure the process doesn't catch the
520 * signal and then access the memory. Just kill it.
522 if (fail
|| tk
->addr
== -EFAULT
) {
523 pr_err("%#lx: forcibly killing %s:%d because of failure to unmap corrupted page\n",
524 pfn
, tk
->tsk
->comm
, tk
->tsk
->pid
);
525 do_send_sig_info(SIGKILL
, SEND_SIG_PRIV
,
526 tk
->tsk
, PIDTYPE_PID
);
530 * In theory the process could have mapped
531 * something else on the address in-between. We could
532 * check for that, but we need to tell the
535 else if (kill_proc(tk
, pfn
, flags
) < 0)
536 pr_err("%#lx: Cannot send advisory machine check signal to %s:%d\n",
537 pfn
, tk
->tsk
->comm
, tk
->tsk
->pid
);
540 put_task_struct(tk
->tsk
);
546 * Find a dedicated thread which is supposed to handle SIGBUS(BUS_MCEERR_AO)
547 * on behalf of the thread group. Return task_struct of the (first found)
548 * dedicated thread if found, and return NULL otherwise.
550 * We already hold rcu lock in the caller, so we don't have to call
551 * rcu_read_lock/unlock() in this function.
553 static struct task_struct
*find_early_kill_thread(struct task_struct
*tsk
)
555 struct task_struct
*t
;
557 for_each_thread(tsk
, t
) {
558 if (t
->flags
& PF_MCE_PROCESS
) {
559 if (t
->flags
& PF_MCE_EARLY
)
562 if (sysctl_memory_failure_early_kill
)
570 * Determine whether a given process is "early kill" process which expects
571 * to be signaled when some page under the process is hwpoisoned.
572 * Return task_struct of the dedicated thread (main thread unless explicitly
573 * specified) if the process is "early kill" and otherwise returns NULL.
575 * Note that the above is true for Action Optional case. For Action Required
576 * case, it's only meaningful to the current thread which need to be signaled
577 * with SIGBUS, this error is Action Optional for other non current
578 * processes sharing the same error page,if the process is "early kill", the
579 * task_struct of the dedicated thread will also be returned.
581 struct task_struct
*task_early_kill(struct task_struct
*tsk
, int force_early
)
586 * Comparing ->mm here because current task might represent
587 * a subthread, while tsk always points to the main thread.
589 if (force_early
&& tsk
->mm
== current
->mm
)
592 return find_early_kill_thread(tsk
);
596 * Collect processes when the error hit an anonymous page.
598 static void collect_procs_anon(struct page
*page
, struct list_head
*to_kill
,
601 struct folio
*folio
= page_folio(page
);
602 struct vm_area_struct
*vma
;
603 struct task_struct
*tsk
;
607 av
= folio_lock_anon_vma_read(folio
, NULL
);
608 if (av
== NULL
) /* Not actually mapped anymore */
611 pgoff
= page_to_pgoff(page
);
613 for_each_process(tsk
) {
614 struct anon_vma_chain
*vmac
;
615 struct task_struct
*t
= task_early_kill(tsk
, force_early
);
619 anon_vma_interval_tree_foreach(vmac
, &av
->rb_root
,
622 if (vma
->vm_mm
!= t
->mm
)
624 if (!page_mapped_in_vma(page
, vma
))
626 add_to_kill_anon_file(t
, page
, vma
, to_kill
);
630 anon_vma_unlock_read(av
);
634 * Collect processes when the error hit a file mapped page.
636 static void collect_procs_file(struct page
*page
, struct list_head
*to_kill
,
639 struct vm_area_struct
*vma
;
640 struct task_struct
*tsk
;
641 struct address_space
*mapping
= page
->mapping
;
644 i_mmap_lock_read(mapping
);
646 pgoff
= page_to_pgoff(page
);
647 for_each_process(tsk
) {
648 struct task_struct
*t
= task_early_kill(tsk
, force_early
);
652 vma_interval_tree_foreach(vma
, &mapping
->i_mmap
, pgoff
,
655 * Send early kill signal to tasks where a vma covers
656 * the page but the corrupted page is not necessarily
658 * Assume applications who requested early kill want
659 * to be informed of all such data corruptions.
661 if (vma
->vm_mm
== t
->mm
)
662 add_to_kill_anon_file(t
, page
, vma
, to_kill
);
666 i_mmap_unlock_read(mapping
);
670 static void add_to_kill_fsdax(struct task_struct
*tsk
, struct page
*p
,
671 struct vm_area_struct
*vma
,
672 struct list_head
*to_kill
, pgoff_t pgoff
)
674 __add_to_kill(tsk
, p
, vma
, to_kill
, 0, pgoff
);
678 * Collect processes when the error hit a fsdax page.
680 static void collect_procs_fsdax(struct page
*page
,
681 struct address_space
*mapping
, pgoff_t pgoff
,
682 struct list_head
*to_kill
)
684 struct vm_area_struct
*vma
;
685 struct task_struct
*tsk
;
687 i_mmap_lock_read(mapping
);
689 for_each_process(tsk
) {
690 struct task_struct
*t
= task_early_kill(tsk
, true);
694 vma_interval_tree_foreach(vma
, &mapping
->i_mmap
, pgoff
, pgoff
) {
695 if (vma
->vm_mm
== t
->mm
)
696 add_to_kill_fsdax(t
, page
, vma
, to_kill
, pgoff
);
700 i_mmap_unlock_read(mapping
);
702 #endif /* CONFIG_FS_DAX */
705 * Collect the processes who have the corrupted page mapped to kill.
707 static void collect_procs(struct page
*page
, struct list_head
*tokill
,
712 if (unlikely(PageKsm(page
)))
713 collect_procs_ksm(page
, tokill
, force_early
);
714 else if (PageAnon(page
))
715 collect_procs_anon(page
, tokill
, force_early
);
717 collect_procs_file(page
, tokill
, force_early
);
720 struct hwpoison_walk
{
726 static void set_to_kill(struct to_kill
*tk
, unsigned long addr
, short shift
)
729 tk
->size_shift
= shift
;
732 static int check_hwpoisoned_entry(pte_t pte
, unsigned long addr
, short shift
,
733 unsigned long poisoned_pfn
, struct to_kill
*tk
)
735 unsigned long pfn
= 0;
737 if (pte_present(pte
)) {
740 swp_entry_t swp
= pte_to_swp_entry(pte
);
742 if (is_hwpoison_entry(swp
))
743 pfn
= swp_offset_pfn(swp
);
746 if (!pfn
|| pfn
!= poisoned_pfn
)
749 set_to_kill(tk
, addr
, shift
);
753 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
754 static int check_hwpoisoned_pmd_entry(pmd_t
*pmdp
, unsigned long addr
,
755 struct hwpoison_walk
*hwp
)
759 unsigned long hwpoison_vaddr
;
761 if (!pmd_present(pmd
))
764 if (pfn
<= hwp
->pfn
&& hwp
->pfn
< pfn
+ HPAGE_PMD_NR
) {
765 hwpoison_vaddr
= addr
+ ((hwp
->pfn
- pfn
) << PAGE_SHIFT
);
766 set_to_kill(&hwp
->tk
, hwpoison_vaddr
, PAGE_SHIFT
);
772 static int check_hwpoisoned_pmd_entry(pmd_t
*pmdp
, unsigned long addr
,
773 struct hwpoison_walk
*hwp
)
779 static int hwpoison_pte_range(pmd_t
*pmdp
, unsigned long addr
,
780 unsigned long end
, struct mm_walk
*walk
)
782 struct hwpoison_walk
*hwp
= walk
->private;
784 pte_t
*ptep
, *mapped_pte
;
787 ptl
= pmd_trans_huge_lock(pmdp
, walk
->vma
);
789 ret
= check_hwpoisoned_pmd_entry(pmdp
, addr
, hwp
);
794 mapped_pte
= ptep
= pte_offset_map_lock(walk
->vma
->vm_mm
, pmdp
,
799 for (; addr
!= end
; ptep
++, addr
+= PAGE_SIZE
) {
800 ret
= check_hwpoisoned_entry(ptep_get(ptep
), addr
, PAGE_SHIFT
,
805 pte_unmap_unlock(mapped_pte
, ptl
);
811 #ifdef CONFIG_HUGETLB_PAGE
812 static int hwpoison_hugetlb_range(pte_t
*ptep
, unsigned long hmask
,
813 unsigned long addr
, unsigned long end
,
814 struct mm_walk
*walk
)
816 struct hwpoison_walk
*hwp
= walk
->private;
817 pte_t pte
= huge_ptep_get(ptep
);
818 struct hstate
*h
= hstate_vma(walk
->vma
);
820 return check_hwpoisoned_entry(pte
, addr
, huge_page_shift(h
),
824 #define hwpoison_hugetlb_range NULL
827 static const struct mm_walk_ops hwpoison_walk_ops
= {
828 .pmd_entry
= hwpoison_pte_range
,
829 .hugetlb_entry
= hwpoison_hugetlb_range
,
830 .walk_lock
= PGWALK_RDLOCK
,
834 * Sends SIGBUS to the current process with error info.
836 * This function is intended to handle "Action Required" MCEs on already
837 * hardware poisoned pages. They could happen, for example, when
838 * memory_failure() failed to unmap the error page at the first call, or
839 * when multiple local machine checks happened on different CPUs.
841 * MCE handler currently has no easy access to the error virtual address,
842 * so this function walks page table to find it. The returned virtual address
843 * is proper in most cases, but it could be wrong when the application
844 * process has multiple entries mapping the error page.
846 static int kill_accessing_process(struct task_struct
*p
, unsigned long pfn
,
850 struct hwpoison_walk priv
= {
858 mmap_read_lock(p
->mm
);
859 ret
= walk_page_range(p
->mm
, 0, TASK_SIZE
, &hwpoison_walk_ops
,
861 if (ret
== 1 && priv
.tk
.addr
)
862 kill_proc(&priv
.tk
, pfn
, flags
);
865 mmap_read_unlock(p
->mm
);
866 return ret
> 0 ? -EHWPOISON
: -EFAULT
;
869 static const char *action_name
[] = {
870 [MF_IGNORED
] = "Ignored",
871 [MF_FAILED
] = "Failed",
872 [MF_DELAYED
] = "Delayed",
873 [MF_RECOVERED
] = "Recovered",
876 static const char * const action_page_types
[] = {
877 [MF_MSG_KERNEL
] = "reserved kernel page",
878 [MF_MSG_KERNEL_HIGH_ORDER
] = "high-order kernel page",
879 [MF_MSG_SLAB
] = "kernel slab page",
880 [MF_MSG_DIFFERENT_COMPOUND
] = "different compound page after locking",
881 [MF_MSG_HUGE
] = "huge page",
882 [MF_MSG_FREE_HUGE
] = "free huge page",
883 [MF_MSG_UNMAP_FAILED
] = "unmapping failed page",
884 [MF_MSG_DIRTY_SWAPCACHE
] = "dirty swapcache page",
885 [MF_MSG_CLEAN_SWAPCACHE
] = "clean swapcache page",
886 [MF_MSG_DIRTY_MLOCKED_LRU
] = "dirty mlocked LRU page",
887 [MF_MSG_CLEAN_MLOCKED_LRU
] = "clean mlocked LRU page",
888 [MF_MSG_DIRTY_UNEVICTABLE_LRU
] = "dirty unevictable LRU page",
889 [MF_MSG_CLEAN_UNEVICTABLE_LRU
] = "clean unevictable LRU page",
890 [MF_MSG_DIRTY_LRU
] = "dirty LRU page",
891 [MF_MSG_CLEAN_LRU
] = "clean LRU page",
892 [MF_MSG_TRUNCATED_LRU
] = "already truncated LRU page",
893 [MF_MSG_BUDDY
] = "free buddy page",
894 [MF_MSG_DAX
] = "dax page",
895 [MF_MSG_UNSPLIT_THP
] = "unsplit thp",
896 [MF_MSG_UNKNOWN
] = "unknown page",
900 * XXX: It is possible that a page is isolated from LRU cache,
901 * and then kept in swap cache or failed to remove from page cache.
902 * The page count will stop it from being freed by unpoison.
903 * Stress tests should be aware of this memory leak problem.
905 static int delete_from_lru_cache(struct page
*p
)
907 if (isolate_lru_page(p
)) {
909 * Clear sensible page flags, so that the buddy system won't
910 * complain when the page is unpoison-and-freed.
913 ClearPageUnevictable(p
);
916 * Poisoned page might never drop its ref count to 0 so we have
917 * to uncharge it manually from its memcg.
919 mem_cgroup_uncharge(page_folio(p
));
922 * drop the page count elevated by isolate_lru_page()
930 static int truncate_error_page(struct page
*p
, unsigned long pfn
,
931 struct address_space
*mapping
)
935 if (mapping
->a_ops
->error_remove_page
) {
936 struct folio
*folio
= page_folio(p
);
937 int err
= mapping
->a_ops
->error_remove_page(mapping
, p
);
940 pr_info("%#lx: Failed to punch page: %d\n", pfn
, err
);
941 else if (!filemap_release_folio(folio
, GFP_NOIO
))
942 pr_info("%#lx: failed to release buffers\n", pfn
);
947 * If the file system doesn't support it just invalidate
948 * This fails on dirty or anything with private pages
950 if (invalidate_inode_page(p
))
953 pr_info("%#lx: Failed to invalidate\n", pfn
);
962 enum mf_action_page_type type
;
964 /* Callback ->action() has to unlock the relevant page inside it. */
965 int (*action
)(struct page_state
*ps
, struct page
*p
);
969 * Return true if page is still referenced by others, otherwise return
972 * The extra_pins is true when one extra refcount is expected.
974 static bool has_extra_refcount(struct page_state
*ps
, struct page
*p
,
977 int count
= page_count(p
) - 1;
983 pr_err("%#lx: %s still referenced by %d users\n",
984 page_to_pfn(p
), action_page_types
[ps
->type
], count
);
992 * Error hit kernel page.
993 * Do nothing, try to be lucky and not touch this instead. For a few cases we
994 * could be more sophisticated.
996 static int me_kernel(struct page_state
*ps
, struct page
*p
)
1003 * Page in unknown state. Do nothing.
1005 static int me_unknown(struct page_state
*ps
, struct page
*p
)
1007 pr_err("%#lx: Unknown page state\n", page_to_pfn(p
));
1013 * Clean (or cleaned) page cache page.
1015 static int me_pagecache_clean(struct page_state
*ps
, struct page
*p
)
1018 struct address_space
*mapping
;
1021 delete_from_lru_cache(p
);
1024 * For anonymous pages we're done the only reference left
1025 * should be the one m_f() holds.
1033 * Now truncate the page in the page cache. This is really
1034 * more like a "temporary hole punch"
1035 * Don't do this for block devices when someone else
1036 * has a reference, because it could be file system metadata
1037 * and that's not safe to truncate.
1039 mapping
= page_mapping(p
);
1042 * Page has been teared down in the meanwhile
1049 * The shmem page is kept in page cache instead of truncating
1050 * so is expected to have an extra refcount after error-handling.
1052 extra_pins
= shmem_mapping(mapping
);
1055 * Truncation is a bit tricky. Enable it per file system for now.
1057 * Open: to take i_rwsem or not for this? Right now we don't.
1059 ret
= truncate_error_page(p
, page_to_pfn(p
), mapping
);
1060 if (has_extra_refcount(ps
, p
, extra_pins
))
1070 * Dirty pagecache page
1071 * Issues: when the error hit a hole page the error is not properly
1074 static int me_pagecache_dirty(struct page_state
*ps
, struct page
*p
)
1076 struct address_space
*mapping
= page_mapping(p
);
1079 /* TBD: print more information about the file. */
1082 * IO error will be reported by write(), fsync(), etc.
1083 * who check the mapping.
1084 * This way the application knows that something went
1085 * wrong with its dirty file data.
1087 * There's one open issue:
1089 * The EIO will be only reported on the next IO
1090 * operation and then cleared through the IO map.
1091 * Normally Linux has two mechanisms to pass IO error
1092 * first through the AS_EIO flag in the address space
1093 * and then through the PageError flag in the page.
1094 * Since we drop pages on memory failure handling the
1095 * only mechanism open to use is through AS_AIO.
1097 * This has the disadvantage that it gets cleared on
1098 * the first operation that returns an error, while
1099 * the PageError bit is more sticky and only cleared
1100 * when the page is reread or dropped. If an
1101 * application assumes it will always get error on
1102 * fsync, but does other operations on the fd before
1103 * and the page is dropped between then the error
1104 * will not be properly reported.
1106 * This can already happen even without hwpoisoned
1107 * pages: first on metadata IO errors (which only
1108 * report through AS_EIO) or when the page is dropped
1109 * at the wrong time.
1111 * So right now we assume that the application DTRT on
1112 * the first EIO, but we're not worse than other parts
1115 mapping_set_error(mapping
, -EIO
);
1118 return me_pagecache_clean(ps
, p
);
1122 * Clean and dirty swap cache.
1124 * Dirty swap cache page is tricky to handle. The page could live both in page
1125 * cache and swap cache(ie. page is freshly swapped in). So it could be
1126 * referenced concurrently by 2 types of PTEs:
1127 * normal PTEs and swap PTEs. We try to handle them consistently by calling
1128 * try_to_unmap(!TTU_HWPOISON) to convert the normal PTEs to swap PTEs,
1130 * - clear dirty bit to prevent IO
1132 * - but keep in the swap cache, so that when we return to it on
1133 * a later page fault, we know the application is accessing
1134 * corrupted data and shall be killed (we installed simple
1135 * interception code in do_swap_page to catch it).
1137 * Clean swap cache pages can be directly isolated. A later page fault will
1138 * bring in the known good data from disk.
1140 static int me_swapcache_dirty(struct page_state
*ps
, struct page
*p
)
1143 bool extra_pins
= false;
1146 /* Trigger EIO in shmem: */
1147 ClearPageUptodate(p
);
1149 ret
= delete_from_lru_cache(p
) ? MF_FAILED
: MF_DELAYED
;
1152 if (ret
== MF_DELAYED
)
1155 if (has_extra_refcount(ps
, p
, extra_pins
))
1161 static int me_swapcache_clean(struct page_state
*ps
, struct page
*p
)
1163 struct folio
*folio
= page_folio(p
);
1166 delete_from_swap_cache(folio
);
1168 ret
= delete_from_lru_cache(p
) ? MF_FAILED
: MF_RECOVERED
;
1169 folio_unlock(folio
);
1171 if (has_extra_refcount(ps
, p
, false))
1178 * Huge pages. Needs work.
1180 * - Error on hugepage is contained in hugepage unit (not in raw page unit.)
1181 * To narrow down kill region to one page, we need to break up pmd.
1183 static int me_huge_page(struct page_state
*ps
, struct page
*p
)
1186 struct page
*hpage
= compound_head(p
);
1187 struct address_space
*mapping
;
1188 bool extra_pins
= false;
1190 mapping
= page_mapping(hpage
);
1192 res
= truncate_error_page(hpage
, page_to_pfn(p
), mapping
);
1193 /* The page is kept in page cache. */
1199 * migration entry prevents later access on error hugepage,
1200 * so we can free and dissolve it into buddy to save healthy
1204 if (__page_handle_poison(p
) >= 0) {
1212 if (has_extra_refcount(ps
, p
, extra_pins
))
1219 * Various page states we can handle.
1221 * A page state is defined by its current page->flags bits.
1222 * The table matches them in order and calls the right handler.
1224 * This is quite tricky because we can access page at any time
1225 * in its live cycle, so all accesses have to be extremely careful.
1227 * This is not complete. More states could be added.
1228 * For any missing state don't attempt recovery.
1231 #define dirty (1UL << PG_dirty)
1232 #define sc ((1UL << PG_swapcache) | (1UL << PG_swapbacked))
1233 #define unevict (1UL << PG_unevictable)
1234 #define mlock (1UL << PG_mlocked)
1235 #define lru (1UL << PG_lru)
1236 #define head (1UL << PG_head)
1237 #define slab (1UL << PG_slab)
1238 #define reserved (1UL << PG_reserved)
1240 static struct page_state error_states
[] = {
1241 { reserved
, reserved
, MF_MSG_KERNEL
, me_kernel
},
1243 * free pages are specially detected outside this table:
1244 * PG_buddy pages only make a small fraction of all free pages.
1248 * Could in theory check if slab page is free or if we can drop
1249 * currently unused objects without touching them. But just
1250 * treat it as standard kernel for now.
1252 { slab
, slab
, MF_MSG_SLAB
, me_kernel
},
1254 { head
, head
, MF_MSG_HUGE
, me_huge_page
},
1256 { sc
|dirty
, sc
|dirty
, MF_MSG_DIRTY_SWAPCACHE
, me_swapcache_dirty
},
1257 { sc
|dirty
, sc
, MF_MSG_CLEAN_SWAPCACHE
, me_swapcache_clean
},
1259 { mlock
|dirty
, mlock
|dirty
, MF_MSG_DIRTY_MLOCKED_LRU
, me_pagecache_dirty
},
1260 { mlock
|dirty
, mlock
, MF_MSG_CLEAN_MLOCKED_LRU
, me_pagecache_clean
},
1262 { unevict
|dirty
, unevict
|dirty
, MF_MSG_DIRTY_UNEVICTABLE_LRU
, me_pagecache_dirty
},
1263 { unevict
|dirty
, unevict
, MF_MSG_CLEAN_UNEVICTABLE_LRU
, me_pagecache_clean
},
1265 { lru
|dirty
, lru
|dirty
, MF_MSG_DIRTY_LRU
, me_pagecache_dirty
},
1266 { lru
|dirty
, lru
, MF_MSG_CLEAN_LRU
, me_pagecache_clean
},
1269 * Catchall entry: must be at end.
1271 { 0, 0, MF_MSG_UNKNOWN
, me_unknown
},
1283 static void update_per_node_mf_stats(unsigned long pfn
,
1284 enum mf_result result
)
1286 int nid
= MAX_NUMNODES
;
1287 struct memory_failure_stats
*mf_stats
= NULL
;
1289 nid
= pfn_to_nid(pfn
);
1290 if (unlikely(nid
< 0 || nid
>= MAX_NUMNODES
)) {
1291 WARN_ONCE(1, "Memory failure: pfn=%#lx, invalid nid=%d", pfn
, nid
);
1295 mf_stats
= &NODE_DATA(nid
)->mf_stats
;
1298 ++mf_stats
->ignored
;
1304 ++mf_stats
->delayed
;
1307 ++mf_stats
->recovered
;
1310 WARN_ONCE(1, "Memory failure: mf_result=%d is not properly handled", result
);
1317 * "Dirty/Clean" indication is not 100% accurate due to the possibility of
1318 * setting PG_dirty outside page lock. See also comment above set_page_dirty().
1320 static int action_result(unsigned long pfn
, enum mf_action_page_type type
,
1321 enum mf_result result
)
1323 trace_memory_failure_event(pfn
, type
, result
);
1325 num_poisoned_pages_inc(pfn
);
1327 update_per_node_mf_stats(pfn
, result
);
1329 pr_err("%#lx: recovery action for %s: %s\n",
1330 pfn
, action_page_types
[type
], action_name
[result
]);
1332 return (result
== MF_RECOVERED
|| result
== MF_DELAYED
) ? 0 : -EBUSY
;
1335 static int page_action(struct page_state
*ps
, struct page
*p
,
1340 /* page p should be unlocked after returning from ps->action(). */
1341 result
= ps
->action(ps
, p
);
1343 /* Could do more checks here if page looks ok */
1345 * Could adjust zone counters here to correct for the missing page.
1348 return action_result(pfn
, ps
->type
, result
);
1351 static inline bool PageHWPoisonTakenOff(struct page
*page
)
1353 return PageHWPoison(page
) && page_private(page
) == MAGIC_HWPOISON
;
1356 void SetPageHWPoisonTakenOff(struct page
*page
)
1358 set_page_private(page
, MAGIC_HWPOISON
);
1361 void ClearPageHWPoisonTakenOff(struct page
*page
)
1363 if (PageHWPoison(page
))
1364 set_page_private(page
, 0);
1368 * Return true if a page type of a given page is supported by hwpoison
1369 * mechanism (while handling could fail), otherwise false. This function
1370 * does not return true for hugetlb or device memory pages, so it's assumed
1371 * to be called only in the context where we never have such pages.
1373 static inline bool HWPoisonHandlable(struct page
*page
, unsigned long flags
)
1375 /* Soft offline could migrate non-LRU movable pages */
1376 if ((flags
& MF_SOFT_OFFLINE
) && __PageMovable(page
))
1379 return PageLRU(page
) || is_free_buddy_page(page
);
1382 static int __get_hwpoison_page(struct page
*page
, unsigned long flags
)
1384 struct folio
*folio
= page_folio(page
);
1386 bool hugetlb
= false;
1388 ret
= get_hwpoison_hugetlb_folio(folio
, &hugetlb
, false);
1390 /* Make sure hugetlb demotion did not happen from under us. */
1391 if (folio
== page_folio(page
))
1395 folio
= page_folio(page
);
1400 * This check prevents from calling folio_try_get() for any
1401 * unsupported type of folio in order to reduce the risk of unexpected
1402 * races caused by taking a folio refcount.
1404 if (!HWPoisonHandlable(&folio
->page
, flags
))
1407 if (folio_try_get(folio
)) {
1408 if (folio
== page_folio(page
))
1411 pr_info("%#lx cannot catch tail\n", page_to_pfn(page
));
1418 static int get_any_page(struct page
*p
, unsigned long flags
)
1420 int ret
= 0, pass
= 0;
1421 bool count_increased
= false;
1423 if (flags
& MF_COUNT_INCREASED
)
1424 count_increased
= true;
1427 if (!count_increased
) {
1428 ret
= __get_hwpoison_page(p
, flags
);
1430 if (page_count(p
)) {
1431 /* We raced with an allocation, retry. */
1435 } else if (!PageHuge(p
) && !is_free_buddy_page(p
)) {
1436 /* We raced with put_page, retry. */
1442 } else if (ret
== -EBUSY
) {
1444 * We raced with (possibly temporary) unhandlable
1456 if (PageHuge(p
) || HWPoisonHandlable(p
, flags
)) {
1460 * A page we cannot handle. Check whether we can turn
1461 * it into something we can handle.
1466 count_increased
= false;
1474 pr_err("%#lx: unhandlable page.\n", page_to_pfn(p
));
1479 static int __get_unpoison_page(struct page
*page
)
1481 struct folio
*folio
= page_folio(page
);
1483 bool hugetlb
= false;
1485 ret
= get_hwpoison_hugetlb_folio(folio
, &hugetlb
, true);
1487 /* Make sure hugetlb demotion did not happen from under us. */
1488 if (folio
== page_folio(page
))
1495 * PageHWPoisonTakenOff pages are not only marked as PG_hwpoison,
1496 * but also isolated from buddy freelist, so need to identify the
1497 * state and have to cancel both operations to unpoison.
1499 if (PageHWPoisonTakenOff(page
))
1502 return get_page_unless_zero(page
) ? 1 : 0;
1506 * get_hwpoison_page() - Get refcount for memory error handling
1507 * @p: Raw error page (hit by memory error)
1508 * @flags: Flags controlling behavior of error handling
1510 * get_hwpoison_page() takes a page refcount of an error page to handle memory
1511 * error on it, after checking that the error page is in a well-defined state
1512 * (defined as a page-type we can successfully handle the memory error on it,
1513 * such as LRU page and hugetlb page).
1515 * Memory error handling could be triggered at any time on any type of page,
1516 * so it's prone to race with typical memory management lifecycle (like
1517 * allocation and free). So to avoid such races, get_hwpoison_page() takes
1518 * extra care for the error page's state (as done in __get_hwpoison_page()),
1519 * and has some retry logic in get_any_page().
1521 * When called from unpoison_memory(), the caller should already ensure that
1522 * the given page has PG_hwpoison. So it's never reused for other page
1523 * allocations, and __get_unpoison_page() never races with them.
1525 * Return: 0 on failure,
1526 * 1 on success for in-use pages in a well-defined state,
1527 * -EIO for pages on which we can not handle memory errors,
1528 * -EBUSY when get_hwpoison_page() has raced with page lifecycle
1529 * operations like allocation and free,
1530 * -EHWPOISON when the page is hwpoisoned and taken off from buddy.
1532 static int get_hwpoison_page(struct page
*p
, unsigned long flags
)
1536 zone_pcp_disable(page_zone(p
));
1537 if (flags
& MF_UNPOISON
)
1538 ret
= __get_unpoison_page(p
);
1540 ret
= get_any_page(p
, flags
);
1541 zone_pcp_enable(page_zone(p
));
1547 * Do all that is necessary to remove user space mappings. Unmap
1548 * the pages and send SIGBUS to the processes if the data was dirty.
1550 static bool hwpoison_user_mappings(struct page
*p
, unsigned long pfn
,
1551 int flags
, struct page
*hpage
)
1553 struct folio
*folio
= page_folio(hpage
);
1554 enum ttu_flags ttu
= TTU_IGNORE_MLOCK
| TTU_SYNC
| TTU_HWPOISON
;
1555 struct address_space
*mapping
;
1559 bool mlocked
= PageMlocked(hpage
);
1562 * Here we are interested only in user-mapped pages, so skip any
1563 * other types of pages.
1565 if (PageReserved(p
) || PageSlab(p
) || PageTable(p
) || PageOffline(p
))
1567 if (!(PageLRU(hpage
) || PageHuge(p
)))
1571 * This check implies we don't kill processes if their pages
1572 * are in the swap cache early. Those are always late kills.
1574 if (!page_mapped(hpage
))
1577 if (PageSwapCache(p
)) {
1578 pr_err("%#lx: keeping poisoned page in swap cache\n", pfn
);
1579 ttu
&= ~TTU_HWPOISON
;
1583 * Propagate the dirty bit from PTEs to struct page first, because we
1584 * need this to decide if we should kill or just drop the page.
1585 * XXX: the dirty test could be racy: set_page_dirty() may not always
1586 * be called inside page lock (it's recommended but not enforced).
1588 mapping
= page_mapping(hpage
);
1589 if (!(flags
& MF_MUST_KILL
) && !PageDirty(hpage
) && mapping
&&
1590 mapping_can_writeback(mapping
)) {
1591 if (page_mkclean(hpage
)) {
1592 SetPageDirty(hpage
);
1594 ttu
&= ~TTU_HWPOISON
;
1595 pr_info("%#lx: corrupted page was clean: dropped without side effects\n",
1601 * First collect all the processes that have the page
1602 * mapped in dirty form. This has to be done before try_to_unmap,
1603 * because ttu takes the rmap data structures down.
1605 collect_procs(hpage
, &tokill
, flags
& MF_ACTION_REQUIRED
);
1607 if (PageHuge(hpage
) && !PageAnon(hpage
)) {
1609 * For hugetlb pages in shared mappings, try_to_unmap
1610 * could potentially call huge_pmd_unshare. Because of
1611 * this, take semaphore in write mode here and set
1612 * TTU_RMAP_LOCKED to indicate we have taken the lock
1613 * at this higher level.
1615 mapping
= hugetlb_page_mapping_lock_write(hpage
);
1617 try_to_unmap(folio
, ttu
|TTU_RMAP_LOCKED
);
1618 i_mmap_unlock_write(mapping
);
1620 pr_info("%#lx: could not lock mapping for mapped huge page\n", pfn
);
1622 try_to_unmap(folio
, ttu
);
1625 unmap_success
= !page_mapped(hpage
);
1627 pr_err("%#lx: failed to unmap page (mapcount=%d)\n",
1628 pfn
, page_mapcount(hpage
));
1631 * try_to_unmap() might put mlocked page in lru cache, so call
1632 * shake_page() again to ensure that it's flushed.
1638 * Now that the dirty bit has been propagated to the
1639 * struct page and all unmaps done we can decide if
1640 * killing is needed or not. Only kill when the page
1641 * was dirty or the process is not restartable,
1642 * otherwise the tokill list is merely
1643 * freed. When there was a problem unmapping earlier
1644 * use a more force-full uncatchable kill to prevent
1645 * any accesses to the poisoned memory.
1647 forcekill
= PageDirty(hpage
) || (flags
& MF_MUST_KILL
) ||
1649 kill_procs(&tokill
, forcekill
, !unmap_success
, pfn
, flags
);
1651 return unmap_success
;
1654 static int identify_page_state(unsigned long pfn
, struct page
*p
,
1655 unsigned long page_flags
)
1657 struct page_state
*ps
;
1660 * The first check uses the current page flags which may not have any
1661 * relevant information. The second check with the saved page flags is
1662 * carried out only if the first check can't determine the page status.
1664 for (ps
= error_states
;; ps
++)
1665 if ((p
->flags
& ps
->mask
) == ps
->res
)
1668 page_flags
|= (p
->flags
& (1UL << PG_dirty
));
1671 for (ps
= error_states
;; ps
++)
1672 if ((page_flags
& ps
->mask
) == ps
->res
)
1674 return page_action(ps
, p
, pfn
);
1677 static int try_to_split_thp_page(struct page
*page
)
1682 ret
= split_huge_page(page
);
1691 static void unmap_and_kill(struct list_head
*to_kill
, unsigned long pfn
,
1692 struct address_space
*mapping
, pgoff_t index
, int flags
)
1695 unsigned long size
= 0;
1697 list_for_each_entry(tk
, to_kill
, nd
)
1699 size
= max(size
, 1UL << tk
->size_shift
);
1703 * Unmap the largest mapping to avoid breaking up device-dax
1704 * mappings which are constant size. The actual size of the
1705 * mapping being torn down is communicated in siginfo, see
1708 loff_t start
= (index
<< PAGE_SHIFT
) & ~(size
- 1);
1710 unmap_mapping_range(mapping
, start
, size
, 0);
1713 kill_procs(to_kill
, flags
& MF_MUST_KILL
, false, pfn
, flags
);
1716 static int mf_generic_kill_procs(unsigned long long pfn
, int flags
,
1717 struct dev_pagemap
*pgmap
)
1719 struct page
*page
= pfn_to_page(pfn
);
1725 * Pages instantiated by device-dax (not filesystem-dax)
1726 * may be compound pages.
1728 page
= compound_head(page
);
1731 * Prevent the inode from being freed while we are interrogating
1732 * the address_space, typically this would be handled by
1733 * lock_page(), but dax pages do not use the page lock. This
1734 * also prevents changes to the mapping of this pfn until
1735 * poison signaling is complete.
1737 cookie
= dax_lock_page(page
);
1741 if (hwpoison_filter(page
)) {
1746 switch (pgmap
->type
) {
1747 case MEMORY_DEVICE_PRIVATE
:
1748 case MEMORY_DEVICE_COHERENT
:
1750 * TODO: Handle device pages which may need coordination
1751 * with device-side memory.
1760 * Use this flag as an indication that the dax page has been
1761 * remapped UC to prevent speculative consumption of poison.
1763 SetPageHWPoison(page
);
1766 * Unlike System-RAM there is no possibility to swap in a
1767 * different physical page at a given virtual address, so all
1768 * userspace consumption of ZONE_DEVICE memory necessitates
1769 * SIGBUS (i.e. MF_MUST_KILL)
1771 flags
|= MF_ACTION_REQUIRED
| MF_MUST_KILL
;
1772 collect_procs(page
, &to_kill
, true);
1774 unmap_and_kill(&to_kill
, pfn
, page
->mapping
, page
->index
, flags
);
1776 dax_unlock_page(page
, cookie
);
1780 #ifdef CONFIG_FS_DAX
1782 * mf_dax_kill_procs - Collect and kill processes who are using this file range
1783 * @mapping: address_space of the file in use
1784 * @index: start pgoff of the range within the file
1785 * @count: length of the range, in unit of PAGE_SIZE
1786 * @mf_flags: memory failure flags
1788 int mf_dax_kill_procs(struct address_space
*mapping
, pgoff_t index
,
1789 unsigned long count
, int mf_flags
)
1794 size_t end
= index
+ count
;
1796 mf_flags
|= MF_ACTION_REQUIRED
| MF_MUST_KILL
;
1798 for (; index
< end
; index
++) {
1800 cookie
= dax_lock_mapping_entry(mapping
, index
, &page
);
1806 SetPageHWPoison(page
);
1808 collect_procs_fsdax(page
, mapping
, index
, &to_kill
);
1809 unmap_and_kill(&to_kill
, page_to_pfn(page
), mapping
,
1812 dax_unlock_mapping_entry(mapping
, index
, cookie
);
1816 EXPORT_SYMBOL_GPL(mf_dax_kill_procs
);
1817 #endif /* CONFIG_FS_DAX */
1819 #ifdef CONFIG_HUGETLB_PAGE
1822 * Struct raw_hwp_page represents information about "raw error page",
1823 * constructing singly linked list from ->_hugetlb_hwpoison field of folio.
1825 struct raw_hwp_page
{
1826 struct llist_node node
;
1830 static inline struct llist_head
*raw_hwp_list_head(struct folio
*folio
)
1832 return (struct llist_head
*)&folio
->_hugetlb_hwpoison
;
1835 bool is_raw_hwpoison_page_in_hugepage(struct page
*page
)
1837 struct llist_head
*raw_hwp_head
;
1838 struct raw_hwp_page
*p
;
1839 struct folio
*folio
= page_folio(page
);
1842 if (!folio_test_hwpoison(folio
))
1845 if (!folio_test_hugetlb(folio
))
1846 return PageHWPoison(page
);
1849 * When RawHwpUnreliable is set, kernel lost track of which subpages
1850 * are HWPOISON. So return as if ALL subpages are HWPOISONed.
1852 if (folio_test_hugetlb_raw_hwp_unreliable(folio
))
1855 mutex_lock(&mf_mutex
);
1857 raw_hwp_head
= raw_hwp_list_head(folio
);
1858 llist_for_each_entry(p
, raw_hwp_head
->first
, node
) {
1859 if (page
== p
->page
) {
1865 mutex_unlock(&mf_mutex
);
1870 static unsigned long __folio_free_raw_hwp(struct folio
*folio
, bool move_flag
)
1872 struct llist_node
*head
;
1873 struct raw_hwp_page
*p
, *next
;
1874 unsigned long count
= 0;
1876 head
= llist_del_all(raw_hwp_list_head(folio
));
1877 llist_for_each_entry_safe(p
, next
, head
, node
) {
1879 SetPageHWPoison(p
->page
);
1881 num_poisoned_pages_sub(page_to_pfn(p
->page
), 1);
1888 static int folio_set_hugetlb_hwpoison(struct folio
*folio
, struct page
*page
)
1890 struct llist_head
*head
;
1891 struct raw_hwp_page
*raw_hwp
;
1892 struct raw_hwp_page
*p
, *next
;
1893 int ret
= folio_test_set_hwpoison(folio
) ? -EHWPOISON
: 0;
1896 * Once the hwpoison hugepage has lost reliable raw error info,
1897 * there is little meaning to keep additional error info precisely,
1898 * so skip to add additional raw error info.
1900 if (folio_test_hugetlb_raw_hwp_unreliable(folio
))
1902 head
= raw_hwp_list_head(folio
);
1903 llist_for_each_entry_safe(p
, next
, head
->first
, node
) {
1904 if (p
->page
== page
)
1908 raw_hwp
= kmalloc(sizeof(struct raw_hwp_page
), GFP_ATOMIC
);
1910 raw_hwp
->page
= page
;
1911 llist_add(&raw_hwp
->node
, head
);
1912 /* the first error event will be counted in action_result(). */
1914 num_poisoned_pages_inc(page_to_pfn(page
));
1917 * Failed to save raw error info. We no longer trace all
1918 * hwpoisoned subpages, and we need refuse to free/dissolve
1919 * this hwpoisoned hugepage.
1921 folio_set_hugetlb_raw_hwp_unreliable(folio
);
1923 * Once hugetlb_raw_hwp_unreliable is set, raw_hwp_page is not
1924 * used any more, so free it.
1926 __folio_free_raw_hwp(folio
, false);
1931 static unsigned long folio_free_raw_hwp(struct folio
*folio
, bool move_flag
)
1934 * hugetlb_vmemmap_optimized hugepages can't be freed because struct
1935 * pages for tail pages are required but they don't exist.
1937 if (move_flag
&& folio_test_hugetlb_vmemmap_optimized(folio
))
1941 * hugetlb_raw_hwp_unreliable hugepages shouldn't be unpoisoned by
1944 if (folio_test_hugetlb_raw_hwp_unreliable(folio
))
1947 return __folio_free_raw_hwp(folio
, move_flag
);
1950 void folio_clear_hugetlb_hwpoison(struct folio
*folio
)
1952 if (folio_test_hugetlb_raw_hwp_unreliable(folio
))
1954 if (folio_test_hugetlb_vmemmap_optimized(folio
))
1956 folio_clear_hwpoison(folio
);
1957 folio_free_raw_hwp(folio
, true);
1961 * Called from hugetlb code with hugetlb_lock held.
1965 * 1 - in-use hugepage
1966 * 2 - not a hugepage
1967 * -EBUSY - the hugepage is busy (try to retry)
1968 * -EHWPOISON - the hugepage is already hwpoisoned
1970 int __get_huge_page_for_hwpoison(unsigned long pfn
, int flags
,
1971 bool *migratable_cleared
)
1973 struct page
*page
= pfn_to_page(pfn
);
1974 struct folio
*folio
= page_folio(page
);
1975 int ret
= 2; /* fallback to normal page handling */
1976 bool count_increased
= false;
1978 if (!folio_test_hugetlb(folio
))
1981 if (flags
& MF_COUNT_INCREASED
) {
1983 count_increased
= true;
1984 } else if (folio_test_hugetlb_freed(folio
)) {
1986 } else if (folio_test_hugetlb_migratable(folio
)) {
1987 ret
= folio_try_get(folio
);
1989 count_increased
= true;
1992 if (!(flags
& MF_NO_RETRY
))
1996 if (folio_set_hugetlb_hwpoison(folio
, page
)) {
2002 * Clearing hugetlb_migratable for hwpoisoned hugepages to prevent them
2003 * from being migrated by memory hotremove.
2005 if (count_increased
&& folio_test_hugetlb_migratable(folio
)) {
2006 folio_clear_hugetlb_migratable(folio
);
2007 *migratable_cleared
= true;
2012 if (count_increased
)
2018 * Taking refcount of hugetlb pages needs extra care about race conditions
2019 * with basic operations like hugepage allocation/free/demotion.
2020 * So some of prechecks for hwpoison (pinning, and testing/setting
2021 * PageHWPoison) should be done in single hugetlb_lock range.
2023 static int try_memory_failure_hugetlb(unsigned long pfn
, int flags
, int *hugetlb
)
2026 struct page
*p
= pfn_to_page(pfn
);
2027 struct folio
*folio
;
2028 unsigned long page_flags
;
2029 bool migratable_cleared
= false;
2033 res
= get_huge_page_for_hwpoison(pfn
, flags
, &migratable_cleared
);
2034 if (res
== 2) { /* fallback to normal page handling */
2037 } else if (res
== -EHWPOISON
) {
2038 pr_err("%#lx: already hardware poisoned\n", pfn
);
2039 if (flags
& MF_ACTION_REQUIRED
) {
2040 folio
= page_folio(p
);
2041 res
= kill_accessing_process(current
, folio_pfn(folio
), flags
);
2044 } else if (res
== -EBUSY
) {
2045 if (!(flags
& MF_NO_RETRY
)) {
2046 flags
|= MF_NO_RETRY
;
2049 return action_result(pfn
, MF_MSG_UNKNOWN
, MF_IGNORED
);
2052 folio
= page_folio(p
);
2055 if (hwpoison_filter(p
)) {
2056 folio_clear_hugetlb_hwpoison(folio
);
2057 if (migratable_cleared
)
2058 folio_set_hugetlb_migratable(folio
);
2059 folio_unlock(folio
);
2066 * Handling free hugepage. The possible race with hugepage allocation
2067 * or demotion can be prevented by PageHWPoison flag.
2070 folio_unlock(folio
);
2071 if (__page_handle_poison(p
) >= 0) {
2077 return action_result(pfn
, MF_MSG_FREE_HUGE
, res
);
2080 page_flags
= folio
->flags
;
2082 if (!hwpoison_user_mappings(p
, pfn
, flags
, &folio
->page
)) {
2083 folio_unlock(folio
);
2084 return action_result(pfn
, MF_MSG_UNMAP_FAILED
, MF_IGNORED
);
2087 return identify_page_state(pfn
, p
, page_flags
);
2091 static inline int try_memory_failure_hugetlb(unsigned long pfn
, int flags
, int *hugetlb
)
2096 static inline unsigned long folio_free_raw_hwp(struct folio
*folio
, bool flag
)
2100 #endif /* CONFIG_HUGETLB_PAGE */
2102 /* Drop the extra refcount in case we come from madvise() */
2103 static void put_ref_page(unsigned long pfn
, int flags
)
2107 if (!(flags
& MF_COUNT_INCREASED
))
2110 page
= pfn_to_page(pfn
);
2115 static int memory_failure_dev_pagemap(unsigned long pfn
, int flags
,
2116 struct dev_pagemap
*pgmap
)
2120 /* device metadata space is not recoverable */
2121 if (!pgmap_pfn_valid(pgmap
, pfn
))
2125 * Call driver's implementation to handle the memory failure, otherwise
2126 * fall back to generic handler.
2128 if (pgmap_has_memory_failure(pgmap
)) {
2129 rc
= pgmap
->ops
->memory_failure(pgmap
, pfn
, 1, flags
);
2131 * Fall back to generic handler too if operation is not
2132 * supported inside the driver/device/filesystem.
2134 if (rc
!= -EOPNOTSUPP
)
2138 rc
= mf_generic_kill_procs(pfn
, flags
, pgmap
);
2140 /* drop pgmap ref acquired in caller */
2141 put_dev_pagemap(pgmap
);
2142 if (rc
!= -EOPNOTSUPP
)
2143 action_result(pfn
, MF_MSG_DAX
, rc
? MF_FAILED
: MF_RECOVERED
);
2148 * memory_failure - Handle memory failure of a page.
2149 * @pfn: Page Number of the corrupted page
2150 * @flags: fine tune action taken
2152 * This function is called by the low level machine check code
2153 * of an architecture when it detects hardware memory corruption
2154 * of a page. It tries its best to recover, which includes
2155 * dropping pages, killing processes etc.
2157 * The function is primarily of use for corruptions that
2158 * happen outside the current execution context (e.g. when
2159 * detected by a background scrubber)
2161 * Must run in process context (e.g. a work queue) with interrupts
2162 * enabled and no spinlocks held.
2164 * Return: 0 for successfully handled the memory error,
2165 * -EOPNOTSUPP for hwpoison_filter() filtered the error event,
2166 * < 0(except -EOPNOTSUPP) on failure.
2168 int memory_failure(unsigned long pfn
, int flags
)
2172 struct dev_pagemap
*pgmap
;
2174 unsigned long page_flags
;
2178 if (!sysctl_memory_failure_recovery
)
2179 panic("Memory failure on page %lx", pfn
);
2181 mutex_lock(&mf_mutex
);
2183 if (!(flags
& MF_SW_SIMULATED
))
2184 hw_memory_failure
= true;
2186 p
= pfn_to_online_page(pfn
);
2188 res
= arch_memory_failure(pfn
, flags
);
2192 if (pfn_valid(pfn
)) {
2193 pgmap
= get_dev_pagemap(pfn
, NULL
);
2194 put_ref_page(pfn
, flags
);
2196 res
= memory_failure_dev_pagemap(pfn
, flags
,
2201 pr_err("%#lx: memory outside kernel control\n", pfn
);
2207 res
= try_memory_failure_hugetlb(pfn
, flags
, &hugetlb
);
2211 if (TestSetPageHWPoison(p
)) {
2212 pr_err("%#lx: already hardware poisoned\n", pfn
);
2214 if (flags
& MF_ACTION_REQUIRED
)
2215 res
= kill_accessing_process(current
, pfn
, flags
);
2216 if (flags
& MF_COUNT_INCREASED
)
2222 * We need/can do nothing about count=0 pages.
2223 * 1) it's a free page, and therefore in safe hand:
2224 * check_new_page() will be the gate keeper.
2225 * 2) it's part of a non-compound high order page.
2226 * Implies some kernel user: cannot stop them from
2227 * R/W the page; let's pray that the page has been
2228 * used and will be freed some time later.
2229 * In fact it's dangerous to directly bump up page count from 0,
2230 * that may make page_ref_freeze()/page_ref_unfreeze() mismatch.
2232 if (!(flags
& MF_COUNT_INCREASED
)) {
2233 res
= get_hwpoison_page(p
, flags
);
2235 if (is_free_buddy_page(p
)) {
2236 if (take_page_off_buddy(p
)) {
2240 /* We lost the race, try again */
2242 ClearPageHWPoison(p
);
2248 res
= action_result(pfn
, MF_MSG_BUDDY
, res
);
2250 res
= action_result(pfn
, MF_MSG_KERNEL_HIGH_ORDER
, MF_IGNORED
);
2253 } else if (res
< 0) {
2254 res
= action_result(pfn
, MF_MSG_UNKNOWN
, MF_IGNORED
);
2259 hpage
= compound_head(p
);
2260 if (PageTransHuge(hpage
)) {
2262 * The flag must be set after the refcount is bumped
2263 * otherwise it may race with THP split.
2264 * And the flag can't be set in get_hwpoison_page() since
2265 * it is called by soft offline too and it is just called
2266 * for !MF_COUNT_INCREASED. So here seems to be the best
2269 * Don't need care about the above error handling paths for
2270 * get_hwpoison_page() since they handle either free page
2271 * or unhandlable page. The refcount is bumped iff the
2272 * page is a valid handlable page.
2274 SetPageHasHWPoisoned(hpage
);
2275 if (try_to_split_thp_page(p
) < 0) {
2276 res
= action_result(pfn
, MF_MSG_UNSPLIT_THP
, MF_IGNORED
);
2279 VM_BUG_ON_PAGE(!page_count(p
), p
);
2283 * We ignore non-LRU pages for good reasons.
2284 * - PG_locked is only well defined for LRU pages and a few others
2285 * - to avoid races with __SetPageLocked()
2286 * - to avoid races with __SetPageSlab*() (and more non-atomic ops)
2287 * The check (unnecessarily) ignores LRU pages being isolated and
2288 * walked by the page reclaim code, however that's not a big loss.
2295 * We're only intended to deal with the non-Compound page here.
2296 * However, the page could have changed compound pages due to
2297 * race window. If this happens, we could try again to hopefully
2298 * handle the page next round.
2300 if (PageCompound(p
)) {
2302 ClearPageHWPoison(p
);
2305 flags
&= ~MF_COUNT_INCREASED
;
2309 res
= action_result(pfn
, MF_MSG_DIFFERENT_COMPOUND
, MF_IGNORED
);
2314 * We use page flags to determine what action should be taken, but
2315 * the flags can be modified by the error containment action. One
2316 * example is an mlocked page, where PG_mlocked is cleared by
2317 * page_remove_rmap() in try_to_unmap_one(). So to determine page status
2318 * correctly, we save a copy of the page flags at this time.
2320 page_flags
= p
->flags
;
2322 if (hwpoison_filter(p
)) {
2323 ClearPageHWPoison(p
);
2331 * __munlock_folio() may clear a writeback page's LRU flag without
2332 * page_lock. We need wait writeback completion for this page or it
2333 * may trigger vfs BUG while evict inode.
2335 if (!PageLRU(p
) && !PageWriteback(p
))
2336 goto identify_page_state
;
2339 * It's very difficult to mess with pages currently under IO
2340 * and in many cases impossible, so we just avoid it here.
2342 wait_on_page_writeback(p
);
2345 * Now take care of user space mappings.
2346 * Abort on fail: __filemap_remove_folio() assumes unmapped page.
2348 if (!hwpoison_user_mappings(p
, pfn
, flags
, p
)) {
2349 res
= action_result(pfn
, MF_MSG_UNMAP_FAILED
, MF_IGNORED
);
2354 * Torn down by someone else?
2356 if (PageLRU(p
) && !PageSwapCache(p
) && p
->mapping
== NULL
) {
2357 res
= action_result(pfn
, MF_MSG_TRUNCATED_LRU
, MF_IGNORED
);
2361 identify_page_state
:
2362 res
= identify_page_state(pfn
, p
, page_flags
);
2363 mutex_unlock(&mf_mutex
);
2368 mutex_unlock(&mf_mutex
);
2371 EXPORT_SYMBOL_GPL(memory_failure
);
2373 #define MEMORY_FAILURE_FIFO_ORDER 4
2374 #define MEMORY_FAILURE_FIFO_SIZE (1 << MEMORY_FAILURE_FIFO_ORDER)
2376 struct memory_failure_entry
{
2381 struct memory_failure_cpu
{
2382 DECLARE_KFIFO(fifo
, struct memory_failure_entry
,
2383 MEMORY_FAILURE_FIFO_SIZE
);
2385 struct work_struct work
;
2388 static DEFINE_PER_CPU(struct memory_failure_cpu
, memory_failure_cpu
);
2391 * memory_failure_queue - Schedule handling memory failure of a page.
2392 * @pfn: Page Number of the corrupted page
2393 * @flags: Flags for memory failure handling
2395 * This function is called by the low level hardware error handler
2396 * when it detects hardware memory corruption of a page. It schedules
2397 * the recovering of error page, including dropping pages, killing
2400 * The function is primarily of use for corruptions that
2401 * happen outside the current execution context (e.g. when
2402 * detected by a background scrubber)
2404 * Can run in IRQ context.
2406 void memory_failure_queue(unsigned long pfn
, int flags
)
2408 struct memory_failure_cpu
*mf_cpu
;
2409 unsigned long proc_flags
;
2410 struct memory_failure_entry entry
= {
2415 mf_cpu
= &get_cpu_var(memory_failure_cpu
);
2416 spin_lock_irqsave(&mf_cpu
->lock
, proc_flags
);
2417 if (kfifo_put(&mf_cpu
->fifo
, entry
))
2418 schedule_work_on(smp_processor_id(), &mf_cpu
->work
);
2420 pr_err("buffer overflow when queuing memory failure at %#lx\n",
2422 spin_unlock_irqrestore(&mf_cpu
->lock
, proc_flags
);
2423 put_cpu_var(memory_failure_cpu
);
2425 EXPORT_SYMBOL_GPL(memory_failure_queue
);
2427 static void memory_failure_work_func(struct work_struct
*work
)
2429 struct memory_failure_cpu
*mf_cpu
;
2430 struct memory_failure_entry entry
= { 0, };
2431 unsigned long proc_flags
;
2434 mf_cpu
= container_of(work
, struct memory_failure_cpu
, work
);
2436 spin_lock_irqsave(&mf_cpu
->lock
, proc_flags
);
2437 gotten
= kfifo_get(&mf_cpu
->fifo
, &entry
);
2438 spin_unlock_irqrestore(&mf_cpu
->lock
, proc_flags
);
2441 if (entry
.flags
& MF_SOFT_OFFLINE
)
2442 soft_offline_page(entry
.pfn
, entry
.flags
);
2444 memory_failure(entry
.pfn
, entry
.flags
);
2449 * Process memory_failure work queued on the specified CPU.
2450 * Used to avoid return-to-userspace racing with the memory_failure workqueue.
2452 void memory_failure_queue_kick(int cpu
)
2454 struct memory_failure_cpu
*mf_cpu
;
2456 mf_cpu
= &per_cpu(memory_failure_cpu
, cpu
);
2457 cancel_work_sync(&mf_cpu
->work
);
2458 memory_failure_work_func(&mf_cpu
->work
);
2461 static int __init
memory_failure_init(void)
2463 struct memory_failure_cpu
*mf_cpu
;
2466 for_each_possible_cpu(cpu
) {
2467 mf_cpu
= &per_cpu(memory_failure_cpu
, cpu
);
2468 spin_lock_init(&mf_cpu
->lock
);
2469 INIT_KFIFO(mf_cpu
->fifo
);
2470 INIT_WORK(&mf_cpu
->work
, memory_failure_work_func
);
2473 register_sysctl_init("vm", memory_failure_table
);
2477 core_initcall(memory_failure_init
);
2480 #define pr_fmt(fmt) "" fmt
2481 #define unpoison_pr_info(fmt, pfn, rs) \
2483 if (__ratelimit(rs)) \
2484 pr_info(fmt, pfn); \
2488 * unpoison_memory - Unpoison a previously poisoned page
2489 * @pfn: Page number of the to be unpoisoned page
2491 * Software-unpoison a page that has been poisoned by
2492 * memory_failure() earlier.
2494 * This is only done on the software-level, so it only works
2495 * for linux injected failures, not real hardware failures
2497 * Returns 0 for success, otherwise -errno.
2499 int unpoison_memory(unsigned long pfn
)
2501 struct folio
*folio
;
2503 int ret
= -EBUSY
, ghp
;
2504 unsigned long count
= 1;
2506 static DEFINE_RATELIMIT_STATE(unpoison_rs
, DEFAULT_RATELIMIT_INTERVAL
,
2507 DEFAULT_RATELIMIT_BURST
);
2509 if (!pfn_valid(pfn
))
2512 p
= pfn_to_page(pfn
);
2513 folio
= page_folio(p
);
2515 mutex_lock(&mf_mutex
);
2517 if (hw_memory_failure
) {
2518 unpoison_pr_info("Unpoison: Disabled after HW memory failure %#lx\n",
2524 if (!PageHWPoison(p
)) {
2525 unpoison_pr_info("Unpoison: Page was already unpoisoned %#lx\n",
2530 if (folio_ref_count(folio
) > 1) {
2531 unpoison_pr_info("Unpoison: Someone grabs the hwpoison page %#lx\n",
2536 if (folio_test_slab(folio
) || PageTable(&folio
->page
) ||
2537 folio_test_reserved(folio
) || PageOffline(&folio
->page
))
2541 * Note that folio->_mapcount is overloaded in SLAB, so the simple test
2542 * in folio_mapped() has to be done after folio_test_slab() is checked.
2544 if (folio_mapped(folio
)) {
2545 unpoison_pr_info("Unpoison: Someone maps the hwpoison page %#lx\n",
2550 if (folio_mapping(folio
)) {
2551 unpoison_pr_info("Unpoison: the hwpoison page has non-NULL mapping %#lx\n",
2556 ghp
= get_hwpoison_page(p
, MF_UNPOISON
);
2560 count
= folio_free_raw_hwp(folio
, false);
2564 ret
= folio_test_clear_hwpoison(folio
) ? 0 : -EBUSY
;
2565 } else if (ghp
< 0) {
2566 if (ghp
== -EHWPOISON
) {
2567 ret
= put_page_back_buddy(p
) ? 0 : -EBUSY
;
2570 unpoison_pr_info("Unpoison: failed to grab page %#lx\n",
2576 count
= folio_free_raw_hwp(folio
, false);
2584 if (TestClearPageHWPoison(p
)) {
2591 mutex_unlock(&mf_mutex
);
2594 num_poisoned_pages_sub(pfn
, 1);
2595 unpoison_pr_info("Unpoison: Software-unpoisoned page %#lx\n",
2596 page_to_pfn(p
), &unpoison_rs
);
2600 EXPORT_SYMBOL(unpoison_memory
);
2602 static bool isolate_page(struct page
*page
, struct list_head
*pagelist
)
2604 bool isolated
= false;
2606 if (PageHuge(page
)) {
2607 isolated
= isolate_hugetlb(page_folio(page
), pagelist
);
2609 bool lru
= !__PageMovable(page
);
2612 isolated
= isolate_lru_page(page
);
2614 isolated
= isolate_movable_page(page
,
2615 ISOLATE_UNEVICTABLE
);
2618 list_add(&page
->lru
, pagelist
);
2620 inc_node_page_state(page
, NR_ISOLATED_ANON
+
2621 page_is_file_lru(page
));
2626 * If we succeed to isolate the page, we grabbed another refcount on
2627 * the page, so we can safely drop the one we got from get_any_page().
2628 * If we failed to isolate the page, it means that we cannot go further
2629 * and we will return an error, so drop the reference we got from
2630 * get_any_page() as well.
2637 * soft_offline_in_use_page handles hugetlb-pages and non-hugetlb pages.
2638 * If the page is a non-dirty unmapped page-cache page, it simply invalidates.
2639 * If the page is mapped, it migrates the contents over.
2641 static int soft_offline_in_use_page(struct page
*page
)
2644 unsigned long pfn
= page_to_pfn(page
);
2645 struct page
*hpage
= compound_head(page
);
2646 char const *msg_page
[] = {"page", "hugepage"};
2647 bool huge
= PageHuge(page
);
2648 LIST_HEAD(pagelist
);
2649 struct migration_target_control mtc
= {
2650 .nid
= NUMA_NO_NODE
,
2651 .gfp_mask
= GFP_USER
| __GFP_MOVABLE
| __GFP_RETRY_MAYFAIL
,
2654 if (!huge
&& PageTransHuge(hpage
)) {
2655 if (try_to_split_thp_page(page
)) {
2656 pr_info("soft offline: %#lx: thp split failed\n", pfn
);
2664 wait_on_page_writeback(page
);
2665 if (PageHWPoison(page
)) {
2668 pr_info("soft offline: %#lx page already poisoned\n", pfn
);
2672 if (!huge
&& PageLRU(page
) && !PageSwapCache(page
))
2674 * Try to invalidate first. This should work for
2675 * non dirty unmapped page cache pages.
2677 ret
= invalidate_inode_page(page
);
2681 pr_info("soft_offline: %#lx: invalidated\n", pfn
);
2682 page_handle_poison(page
, false, true);
2686 if (isolate_page(hpage
, &pagelist
)) {
2687 ret
= migrate_pages(&pagelist
, alloc_migration_target
, NULL
,
2688 (unsigned long)&mtc
, MIGRATE_SYNC
, MR_MEMORY_FAILURE
, NULL
);
2690 bool release
= !huge
;
2692 if (!page_handle_poison(page
, huge
, release
))
2695 if (!list_empty(&pagelist
))
2696 putback_movable_pages(&pagelist
);
2698 pr_info("soft offline: %#lx: %s migration failed %ld, type %pGp\n",
2699 pfn
, msg_page
[huge
], ret
, &page
->flags
);
2704 pr_info("soft offline: %#lx: %s isolation failed, page count %d, type %pGp\n",
2705 pfn
, msg_page
[huge
], page_count(page
), &page
->flags
);
2712 * soft_offline_page - Soft offline a page.
2713 * @pfn: pfn to soft-offline
2714 * @flags: flags. Same as memory_failure().
2716 * Returns 0 on success
2717 * -EOPNOTSUPP for hwpoison_filter() filtered the error event
2718 * < 0 otherwise negated errno.
2720 * Soft offline a page, by migration or invalidation,
2721 * without killing anything. This is for the case when
2722 * a page is not corrupted yet (so it's still valid to access),
2723 * but has had a number of corrected errors and is better taken
2726 * The actual policy on when to do that is maintained by
2729 * This should never impact any application or cause data loss,
2730 * however it might take some time.
2732 * This is not a 100% solution for all memory, but tries to be
2733 * ``good enough'' for the majority of memory.
2735 int soft_offline_page(unsigned long pfn
, int flags
)
2738 bool try_again
= true;
2741 if (!pfn_valid(pfn
)) {
2742 WARN_ON_ONCE(flags
& MF_COUNT_INCREASED
);
2746 /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
2747 page
= pfn_to_online_page(pfn
);
2749 put_ref_page(pfn
, flags
);
2753 mutex_lock(&mf_mutex
);
2755 if (PageHWPoison(page
)) {
2756 pr_info("%s: %#lx page already poisoned\n", __func__
, pfn
);
2757 put_ref_page(pfn
, flags
);
2758 mutex_unlock(&mf_mutex
);
2764 ret
= get_hwpoison_page(page
, flags
| MF_SOFT_OFFLINE
);
2767 if (hwpoison_filter(page
)) {
2771 mutex_unlock(&mf_mutex
);
2776 ret
= soft_offline_in_use_page(page
);
2777 } else if (ret
== 0) {
2778 if (!page_handle_poison(page
, true, false)) {
2781 flags
&= ~MF_COUNT_INCREASED
;
2788 mutex_unlock(&mf_mutex
);