From: Chris Mason <clm@fb.com>
Date: Wed, 21 May 2014 12:49:54 +0000 (-0700)
Subject: Btrfs: fix double free in find_lock_delalloc_range
X-Git-Tag: v3.2.61~55
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=232270aa2ac2e463afd41cd38665ddb275277d79;p=thirdparty%2Fkernel%2Fstable.git

Btrfs: fix double free in find_lock_delalloc_range

commit 7d78874273463a784759916fc3e0b4e2eb141c70 upstream.

We need to NULL the cached_state after freeing it, otherwise
we might free it again if find_delalloc_range doesn't find anything.

Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index 73e4cbc340b47..05937a8edfde2 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -1523,6 +1523,7 @@ again:
 		 * shortening the size of the delalloc range we're searching
 		 */
 		free_extent_state(cached_state);
+		cached_state = NULL;
 		if (!loops) {
 			unsigned long offset = (*start) & (PAGE_CACHE_SIZE - 1);
 			max_bytes = PAGE_CACHE_SIZE - offset;