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authorKefeng Wang <wangkefeng.wang@huawei.com>2022-12-09 10:28:01 +0300
committerAndrew Morton <akpm@linux-foundation.org>2023-02-10 02:56:51 +0300
commit6b970599e807ea95c653926d41b095a92fd381e2 (patch)
tree5ae0aeb6870eebe132590664658c4deb42027dc0 /mm/swapfile.c
parent55d77bae73426237b3c74c1757a894b056550dff (diff)
downloadlinux-6b970599e807ea95c653926d41b095a92fd381e2.tar.xz
mm: hwpoison: support recovery from ksm_might_need_to_copy()
When the kernel copies a page from ksm_might_need_to_copy(), but runs into an uncorrectable error, it will crash since poisoned page is consumed by kernel, this is similar to the issue recently fixed by Copy-on-write poison recovery. When an error is detected during the page copy, return VM_FAULT_HWPOISON in do_swap_page(), and install a hwpoison entry in unuse_pte() when swapoff, which help us to avoid system crash. Note, memory failure on a KSM page will be skipped, but still call memory_failure_queue() to be consistent with general memory failure process, and we could support KSM page recovery in the feature. [wangkefeng.wang@huawei.com: enhance unuse_pte(), fix issue found by lkp] Link: https://lkml.kernel.org/r/20221213120523.141588-1-wangkefeng.wang@huawei.com [wangkefeng.wang@huawei.com: update changelog, alter ksm_might_need_to_copy(), restore unlikely() in unuse_pte()] Link: https://lkml.kernel.org/r/20230201074433.96641-1-wangkefeng.wang@huawei.com Link: https://lkml.kernel.org/r/20221209072801.193221-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com> Reviewed-by: Naoya Horiguchi <naoya.horiguchi@nec.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: Tony Luck <tony.luck@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/swapfile.c')
-rw-r--r--mm/swapfile.c20
1 files changed, 14 insertions, 6 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 4fa440e87cd6..eb9b0bf1fcdd 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1764,12 +1764,15 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
struct page *swapcache;
spinlock_t *ptl;
pte_t *pte, new_pte;
+ bool hwposioned = false;
int ret = 1;
swapcache = page;
page = ksm_might_need_to_copy(page, vma, addr);
if (unlikely(!page))
return -ENOMEM;
+ else if (unlikely(PTR_ERR(page) == -EHWPOISON))
+ hwposioned = true;
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (unlikely(!pte_same_as_swp(*pte, swp_entry_to_pte(entry)))) {
@@ -1777,15 +1780,19 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
goto out;
}
- if (unlikely(!PageUptodate(page))) {
- pte_t pteval;
+ if (unlikely(hwposioned || !PageUptodate(page))) {
+ swp_entry_t swp_entry;
dec_mm_counter(vma->vm_mm, MM_SWAPENTS);
- pteval = swp_entry_to_pte(make_swapin_error_entry());
- set_pte_at(vma->vm_mm, addr, pte, pteval);
- swap_free(entry);
+ if (hwposioned) {
+ swp_entry = make_hwpoison_entry(swapcache);
+ page = swapcache;
+ } else {
+ swp_entry = make_swapin_error_entry();
+ }
+ new_pte = swp_entry_to_pte(swp_entry);
ret = 0;
- goto out;
+ goto setpte;
}
/* See do_swap_page() */
@@ -1817,6 +1824,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
new_pte = pte_mksoft_dirty(new_pte);
if (pte_swp_uffd_wp(*pte))
new_pte = pte_mkuffd_wp(new_pte);
+setpte:
set_pte_at(vma->vm_mm, addr, pte, new_pte);
swap_free(entry);
out: