Sorry, my fault. It's already validated in unlock_anon_vma_root().
BR
Leon
-----Original Message-----
From: Ma, Xindong
Sent: Wednesday, May 07, 2014 10:32 AM
To: akpm@xxxxxxxxxxxxxxxxxxxx; iamjoonsoo.kim@xxxxxxx; n-horiguchi@xxxxxxxxxxxxx; kirill.shutemov@xxxxxxxxxxxxxxx; gorcunov@xxxxxxxxx; linux-mm@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
Cc: Ma, Xindong
Subject: [PATCH] rmap: validate pointer in anon_vma_clone
If memory allocation failed in first loop, root will be NULL and will lead to kernel panic.
Signed-off-by: Leon Ma <xindong.ma@xxxxxxxxx>
---
mm/rmap.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/mm/rmap.c b/mm/rmap.c
index 9c3e773..6e53aed 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -246,8 +246,10 @@ int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
avc = anon_vma_chain_alloc(GFP_NOWAIT | __GFP_NOWARN);
if (unlikely(!avc)) {
- unlock_anon_vma_root(root);
- root = NULL;
+ if (!root) {
+ unlock_anon_vma_root(root);
+ root = NULL;
+ }
avc = anon_vma_chain_alloc(GFP_KERNEL);
if (!avc)
goto enomem_failure;
--
1.7.9.5
--
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