From 6139919133377652992a5fe134e22abce3e9c25e Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Mon, 30 Jul 2012 18:19:45 -0700 Subject: [PATCH] libceph: recheck con state after allocating incoming message We drop the lock when calling the ->alloc_msg() con op, which means we need to (a) not clobber con->in_msg without the mutex held, and (b) we need to verify that we are still in the OPEN state when we retake it to avoid causing any mayhem. If the state does change, -EAGAIN will get us back to con_work() and loop. Signed-off-by: Sage Weil Reviewed-by: Alex Elder --- net/ceph/messenger.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 13b549b6b1b..b6655b13155 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2735,9 +2735,16 @@ static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip) BUG_ON(con->in_msg != NULL); if (con->ops->alloc_msg) { + struct ceph_msg *msg; + mutex_unlock(&con->mutex); - con->in_msg = con->ops->alloc_msg(con, hdr, skip); + msg = con->ops->alloc_msg(con, hdr, skip); mutex_lock(&con->mutex); + if (con->state != CON_STATE_OPEN) { + ceph_msg_put(msg); + return -EAGAIN; + } + con->in_msg = msg; if (con->in_msg) { con->in_msg->con = con->ops->get(con); BUG_ON(con->in_msg->con == NULL); -- 2.41.0