The issue here is that btrfs_commit_transaction() frees "trans" on both
the error and the success path. So the problem would be if
btrfs_commit_transaction() succeeds, and then qgroup_rescan_init()
fails. That means that "ret" is non-zero and "trans" is non-NULL and it
leads to a use after free inside the btrfs_end_transaction() macro.
Fixes: 340f1aa27f36 ("btrfs: qgroups: Move transaction management inside btrfs_quota_enable/disable")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
diff --git a/fs/btrfs/qgroup.c b/fs/btrfs/qgroup.c
index 4353bb69bb86..d4917c0cddf5 100644
--- a/fs/btrfs/qgroup.c
+++ b/fs/btrfs/qgroup.c
@@ -1019,10 +1019,9 @@ int btrfs_quota_enable(struct btrfs_fs_info *fs_info)
spin_unlock(&fs_info->qgroup_lock);
ret = btrfs_commit_transaction(trans);
- if (ret) {
- trans = NULL;
+ trans = NULL;
+ if (ret)
goto out_free_path;
- }
ret = qgroup_rescan_init(fs_info, 0, 1);
if (!ret) {
