From 71f2cc64d027d712f29bf8d09d3e123302d5f245 Mon Sep 17 00:00:00 2001 From: Luis Henriques Date: Mon, 5 Nov 2018 19:00:52 +0000 Subject: [PATCH] ceph: quota: fix null pointer dereference in quota check MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Luis Henriques Reviewed-by: "Yan, Zheng" Signed-off-by: Ilya Dryomov --- 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 32d4f13784ba..03f4d24db8fe 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;