diff options
author | Andrey Ryabinin <a.ryabinin@samsung.com> | 2014-06-06 19:09:30 +0400 |
---|---|---|
committer | Ben Hutchings <ben@decadent.org.uk> | 2014-07-11 13:33:50 +0100 |
commit | d857054b1160cdc83ad0c3dc4db406dbabcf125b (patch) | |
tree | 6a2366f0e46556f261e4a4e1612145b502192546 /mm | |
parent | 2aef2e3b9192dc9f99eb1061fa2206eb399e7740 (diff) |
mm: rmap: fix use-after-free in __put_anon_vma
commit 624483f3ea82598ab0f62f1bdb9177f531ab1892 upstream.
While working address sanitizer for kernel I've discovered
use-after-free bug in __put_anon_vma.
For the last anon_vma, anon_vma->root freed before child anon_vma.
Later in anon_vma_free(anon_vma) we are referencing to already freed
anon_vma->root to check rwsem.
This fixes it by freeing the child anon_vma before freeing
anon_vma->root.
Signed-off-by: Andrey Ryabinin <a.ryabinin@samsung.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/rmap.c | 3 |
1 files changed, 1 insertions, 2 deletions
diff --git a/mm/rmap.c b/mm/rmap.c index ae27d95072c8..f3f6fd398b32 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1671,10 +1671,9 @@ void __put_anon_vma(struct anon_vma *anon_vma) { struct anon_vma *root = anon_vma->root; + anon_vma_free(anon_vma); if (root != anon_vma && atomic_dec_and_test(&root->refcount)) anon_vma_free(root); - - anon_vma_free(anon_vma); } #ifdef CONFIG_MIGRATION |