ceph: fix null pointer dereference in ceph_flush_snaps()

Signed-off-by: Yan, Zheng <zyan@redhat.com>

1 files changed, 4 insertions, 1 deletions

diff --git a/fs/ceph/caps.c b/fs/ceph/caps.c
index 99115cae1652..16e6ded0b7f2 100644
--- a/fs/ceph/caps.c
+++ b/fs/ceph/caps.c
@@ -1347,9 +1347,12 @@ void ceph_flush_snaps(struct ceph_inode_info *ci,
 {
         struct inode *inode = &ci->vfs_inode;
         struct ceph_mds_client *mdsc = ceph_inode_to_client(inode)->mdsc;
-        struct ceph_mds_session *session = *psession;
+        struct ceph_mds_session *session = NULL;
         int mds;
+
         dout("ceph_flush_snaps %p\n", inode);
+        if (psession)
+                session = *psession;
 retry:
         spin_lock(&ci->i_ceph_lock);
         if (!(ci->i_ceph_flags & CEPH_I_FLUSH_SNAPS)) {