The patch titled
Subject: mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled-v4
has been added to the -mm tree. Its filename is
mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled-v4.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled-v4.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled-v4.patch
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------------------------------------------------------
From: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Subject: mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled-v4
if the vma is out of date, just exit
Link: http://lkml.kernel.org/r/20200416025034.29780-1-songmuchun@xxxxxxxxxxxxx
Fixes: e86c59b1b12d ("mm/ksm: improve deduplication of zero pages with colouring")
Signed-off-by: Muchun Song <songmuchun@xxxxxxxxxxxxx>
Co-developed-by: Xiongchun Duan <duanxiongchun@xxxxxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
Cc: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Markus Elfring <Markus.Elfring@xxxxxx>
Cc: Yang Shi <yang.shi@xxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/ksm.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
--- a/mm/ksm.c~mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled-v4
+++ a/mm/ksm.c
@@ -2116,7 +2116,11 @@ static void cmp_and_merge_page(struct pa
err = try_to_merge_one_page(vma, page,
ZERO_PAGE(rmap_item->address));
else
- err = -EFAULT;
+ /**
+ * If the vma is out of date, we do not need to
+ * continue.
+ */
+ err = 0;
up_read(&mm->mmap_sem);
/*
* In case of failure, the page was not really empty, so we
_
Patches currently in -mm which might be from songmuchun@xxxxxxxxxxxxx are
mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled.patch
mm-ksm-fix-null-pointer-dereference-when-ksm-zero-page-is-enabled-v4.patch
