[PATCH 3.12 203/206] Btrfs: fix kfree on list_head in btrfs_lookup_csums_range error cleanup

[Jiri Slaby]

From: Chris Mason <clm@xxxxxx>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 6e5aafb27419f32575b27ef9d6a31e5d54661aca upstream.

If we hit any errors in btrfs_lookup_csums_range, we'll loop through all
the csums we allocate and free them.  But the code was using list_entry
incorrectly, and ended up trying to free the on-stack list_head instead.

This bug came from commit 0678b6185

btrfs: Don't BUG_ON kzalloc error in btrfs_lookup_csums_range()

Signed-off-by: Chris Mason <clm@xxxxxx>
Reported-by: Erik Berg <btrfs@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
 fs/btrfs/file-item.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c
index d4731e9808ea..ced6aa4ca3c3 100644
--- a/fs/btrfs/file-item.c
+++ b/fs/btrfs/file-item.c
@@ -420,7 +420,7 @@ int btrfs_lookup_csums_range(struct btrfs_root *root, u64 start, u64 end,
 	ret = 0;
 fail:
 	while (ret < 0 && !list_empty(&tmplist)) {
-		sums = list_entry(&tmplist, struct btrfs_ordered_sum, list);
+		sums = list_entry(tmplist.next, struct btrfs_ordered_sum, list);
 		list_del(&sums->list);
 		kfree(sums);
 	}
-- 
2.1.3

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