From 7246240c7c186542f73af4fadc744d66440f616f Mon Sep 17 00:00:00 2001 From: Sage Weil Date: Thu, 25 Oct 2012 08:49:41 -0700 Subject: [PATCH] libceph: avoid NULL kref_put from NULL alloc_msg return The ceph_on_in_msg_alloc() method calls the ->alloc_msg() helper which may return NULL. It also drops con->mutex while it allocates a message, which means that the connection state may change (e.g., get closed). If that happens, we clean up and bail out. Avoid calling ceph_msg_put() on a NULL return value and triggering a crash. This was observed when an ->alloc_msg() call races with a timeout that resends a zillion messages and resets the connection, and ->alloc_msg() returns NULL (because the request was resent to another target). Fixes http://tracker.newdream.net/issues/3342 Signed-off-by: Sage Weil Reviewed-by: Alex Elder --- net/ceph/messenger.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/ceph/messenger.c b/net/ceph/messenger.c index 66f6f56..1041114 100644 --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2742,7 +2742,8 @@ static int ceph_con_in_msg_alloc(struct ceph_connection *con, int *skip) msg = con->ops->alloc_msg(con, hdr, skip); mutex_lock(&con->mutex); if (con->state != CON_STATE_OPEN) { - ceph_msg_put(msg); + if (msg) + ceph_msg_put(msg); return -EAGAIN; } con->in_msg = msg; -- 2.7.4