diff options
| author | Andrey Ryabinin <a.ryabinin@samsung.com> | 2014-06-06 19:09:30 +0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-06-11 11:54:13 -0700 |
| commit | 3ed6413483c7a43b9d38111357ce99afab441717 (patch) | |
| tree | fcd304564241cac87693e76f0d2ae170f588d8db | |
| parent | 395982ce12b3aba14a197ead3e5828e77e11aec1 (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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -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 d3cbac508c2..5d91bb71e75 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1554,10 +1554,9 @@ 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); } static struct anon_vma *rmap_walk_anon_lock(struct page *page, |