ceph: fix uninitialized dentry pointer in ceph_real_mount()

    fs/ceph/super.c: In function ‘ceph_real_mount’:
    fs/ceph/super.c:818: warning: ‘root’ may be used uninitialized in this function

If s_root is already valid, dentry pointer root is never initialized,
and returned by ceph_real_mount(). This will cause a crash later when
the caller dereferences the pointer.

Fixes: ce2728aaa82bbeba ("ceph: avoid accessing / when mounting a subpath")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Yan, Zheng <zyan@redhat.com>

diff --git a/fs/ceph/super.c b/fs/ceph/super.c
index a29ffce981879d5fe46f3858ee90c2fd840f98c1..b382e5910eea8bf7cf7a4711fac79104e6466224 100644 (file)
--- a/fs/ceph/super.c
+++ b/fs/ceph/super.c
@@ -845,6 +845,8 @@ static struct dentry *ceph_real_mount(struct ceph_fs_client *fsc)
                err = ceph_fs_debugfs_init(fsc);
                if (err < 0)
                        goto fail;
+       } else {
+               root = dget(fsc->sb->s_root);
        }
 
        fsc->mount_state = CEPH_MOUNT_MOUNTED;