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* [PATCH -next resend] mm: hwposion: support recovery from ksm_might_need_to_copy()
@ 2022-12-09  2:15 Kefeng Wang
  2022-12-09  6:54 ` kernel test robot
  2022-12-09  7:28 ` [PATCH -next v2] " Kefeng Wang
  0 siblings, 2 replies; 7+ messages in thread
From: Kefeng Wang @ 2022-12-09  2:15 UTC (permalink / raw)
  To: naoya.horiguchi, akpm, linux-mm
  Cc: tony.luck, linux-kernel, linmiaohe, Kefeng Wang

When the kernel copy 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 Copy-on-write poison recovery,
When an error is detected during the page copy, return VM_FAULT_HWPOISON,
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.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
---
 mm/ksm.c      | 8 ++++++--
 mm/memory.c   | 3 +++
 mm/swapfile.c | 2 +-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index dd02780c387f..83e2f74ae7da 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -2629,8 +2629,12 @@ struct page *ksm_might_need_to_copy(struct page *page,
 		new_page = NULL;
 	}
 	if (new_page) {
-		copy_user_highpage(new_page, page, address, vma);
-
+		if (copy_mc_user_highpage(new_page, page, address, vma)) {
+			put_page(new_page);
+			new_page = ERR_PTR(-EHWPOISON);
+			memory_failure_queue(page_to_pfn(page), 0);
+			return new_page;
+		}
 		SetPageDirty(new_page);
 		__SetPageUptodate(new_page);
 		__SetPageLocked(new_page);
diff --git a/mm/memory.c b/mm/memory.c
index aad226daf41b..8711488f5305 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -3840,6 +3840,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf)
 		if (unlikely(!page)) {
 			ret = VM_FAULT_OOM;
 			goto out_page;
+		} els if (unlikely(PTR_ERR(page) == -EHWPOISON)) {
+			ret = VM_FAULT_HWPOISON;
+			goto out_page;
 		}
 		folio = page_folio(page);
 
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 908a529bca12..d479811bc311 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1767,7 +1767,7 @@ static int unuse_pte(struct vm_area_struct *vma, pmd_t *pmd,
 
 	swapcache = page;
 	page = ksm_might_need_to_copy(page, vma, addr);
-	if (unlikely(!page))
+	if (IS_ERR_OR_NULL(page))
 		return -ENOMEM;
 
 	pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
-- 
2.35.3



^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2022-12-12 11:41 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-12-09  2:15 [PATCH -next resend] mm: hwposion: support recovery from ksm_might_need_to_copy() Kefeng Wang
2022-12-09  6:54 ` kernel test robot
2022-12-09  7:28 ` [PATCH -next v2] " Kefeng Wang
2022-12-10  0:50   ` Andrew Morton
2022-12-10  3:37     ` Kefeng Wang
2022-12-12  2:36   ` Miaohe Lin
2022-12-12 11:41     ` Kefeng Wang

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