rbd: Clear ceph_msg->bio_iter for retransmitted message

(cherry picked from commit 43643528cce60ca184fe8197efa8e8da7c89a037)
(cherry picked from commit b132cf4c733f91bb4dd2277ea049243cf16e8b66)

The bug can cause NULL pointer dereference in write_partial_msg_pages

Signed-off-by: Zheng Yan <zheng.z.yan@intel.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c
index 1a80907..375ae39 100644 (file)
--- a/net/ceph/messenger.c
+++ b/net/ceph/messenger.c
@@ -563,6 +563,10 @@ static void prepare_write_message(struct ceph_connection *con)
                m->hdr.seq = cpu_to_le64(++con->out_seq);
                m->needs_out_seq = false;
        }
+#ifdef CONFIG_BLOCK
+       else
+               m->bio_iter = NULL;
+#endif
 
        dout("prepare_write_message %p seq %lld type %d len %d+%d+%d %d pgs\n",
             m, con->out_seq, le16_to_cpu(m->hdr.type),