From: Nikolay Borisov nborisov@suse.com
[ Upstream commit 315bed43fea532650933e7bba316a7601d439edf ]
In btrfs_search_old_slot get_old_root is always used with the assumption it cannot fail. However, this is not true in rare circumstance it can fail and return null. This will lead to null point dereference when the header is read. Fix this by checking the return value and properly handling NULL by setting ret to -EIO and returning gracefully.
Coverity-id: 1087503 Signed-off-by: Nikolay Borisov nborisov@suse.com Reviewed-by: Lu Fengqi lufq.fnst@cn.fujitsu.com Reviewed-by: David Sterba dsterba@suse.com Signed-off-by: David Sterba dsterba@suse.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/btrfs/ctree.c | 4 ++++ 1 file changed, 4 insertions(+)
diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index 3df434eb14743..3faccbf35e9f4 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -2973,6 +2973,10 @@ int btrfs_search_old_slot(struct btrfs_root *root, struct btrfs_key *key,
again: b = get_old_root(root, time_seq); + if (!b) { + ret = -EIO; + goto done; + } level = btrfs_header_level(b); p->locks[level] = BTRFS_READ_LOCK;