[PATCH 5.8 061/148] ceph: fix use-after-free for fsc->mdsc

[Greg Kroah-Hartman]

From: Xiubo Li <xiu...@redhat.com>

[ Upstream commit a7caa88f8b72c136f9a401f498471b8a8e35370d ]

If the ceph_mdsc_init() fails, it will free the mdsc already.

Reported-by: syzbot+b57f46d8d6ea51960...@syzkaller.appspotmail.com
Signed-off-by: Xiubo Li <xiu...@redhat.com>
Reviewed-by: Jeff Layton <jlay...@kernel.org>
Signed-off-by: Ilya Dryomov <idryo...@gmail.com>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 fs/ceph/mds_client.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/ceph/mds_client.c b/fs/ceph/mds_client.c
index dea971f9d89ee..946f9a92658ab 100644
--- a/fs/ceph/mds_client.c
+++ b/fs/ceph/mds_client.c
@@ -4361,7 +4361,6 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
                goto err_mdsc;
        }
 
-       fsc->mdsc = mdsc;
        init_completion(&mdsc->safe_umount_waiters);
        init_waitqueue_head(&mdsc->session_close_wq);
        INIT_LIST_HEAD(&mdsc->waiting_for_map);
@@ -4416,6 +4415,8 @@ int ceph_mdsc_init(struct ceph_fs_client *fsc)
 
        strscpy(mdsc->nodename, utsname()->nodename,
                sizeof(mdsc->nodename));
+
+       fsc->mdsc = mdsc;
        return 0;
 
 err_mdsmap:
-- 
2.25.1