From: Luis Henriques <lhenriques@xxxxxxxx> [ Upstream commit 71f2cc64d027d712f29bf8d09d3e123302d5f245 ] This patch fixes a possible null pointer dereference in check_quota_exceeded, detected by the static checker smatch, with the following warning: fs/ceph/quota.c:240 check_quota_exceeded() error: we previously assumed 'realm' could be null (see line 188) Fixes: b7a2921765cf ("ceph: quota: support for ceph.quota.max_files") Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx> Signed-off-by: Luis Henriques <lhenriques@xxxxxxxx> Reviewed-by: "Yan, Zheng" <zyan@xxxxxxxxxx> Signed-off-by: Ilya Dryomov <idryomov@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/ceph/quota.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/ceph/quota.c b/fs/ceph/quota.c index 242bfa5c0539..47cc6f41d100 100644 --- a/fs/ceph/quota.c +++ b/fs/ceph/quota.c @@ -237,7 +237,8 @@ static bool check_quota_exceeded(struct inode *inode, enum quota_check_op op, ceph_put_snap_realm(mdsc, realm); realm = next; } - ceph_put_snap_realm(mdsc, realm); + if (realm) + ceph_put_snap_realm(mdsc, realm); up_read(&mdsc->snap_rwsem); return exceeded; -- 2.17.1