The patch titled
Subject: mm: hwposion: support recovery from ksm_might_need_to_copy()
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-hwposion-support-recovery-from-ksm_might_need_to_copy-v3.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hwposion-support-recovery-from-ksm_might_need_to_copy-v3.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Subject: mm: hwposion: support recovery from ksm_might_need_to_copy()
Date: Tue, 13 Dec 2022 20:05:23 +0800
- enhance unuse_pte() if ksm_might_need_to_copy() return -EHWPOISON
- fix issue found by lkp
Link: https://lkml.kernel.org/r/20221213120523.141588-1-wangkefeng.wang@xxxxxxxxxx
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
Cc: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
--- a/mm/swapfile.c~mm-hwposion-support-recovery-from-ksm_might_need_to_copy-v3
+++ a/mm/swapfile.c
@@ -1763,12 +1763,15 @@ static int unuse_pte(struct vm_area_stru
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 (IS_ERR_OR_NULL(page))
+ 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)))) {
@@ -1776,15 +1779,19 @@ static int unuse_pte(struct vm_area_stru
goto out;
}
- if (unlikely(!PageUptodate(page))) {
- pte_t pteval;
+ if (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() */
@@ -1816,6 +1823,7 @@ static int unuse_pte(struct vm_area_stru
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:
_
Patches currently in -mm which might be from wangkefeng.wang@xxxxxxxxxx are
mm-hwposion-support-recovery-from-ksm_might_need_to_copy.patch
mm-hwposion-support-recovery-from-ksm_might_need_to_copy-v3.patch
