Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg Kroah-Hartman , alan@lxorguk.ukuu.org.uk, Sage Weil Subject: [ 166/171] libceph: avoid NULL kref_put when osd reset races with alloc_msg Date: Wed, 21 Nov 2012 16:41:52 -0800 Message-Id: <20121122004050.001251870@linuxfoundation.org> In-Reply-To: <20121122004033.298367941@linuxfoundation.org> References: <20121122004033.298367941@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sage Weil (cherry picked from commit 9bd952615a42d7e2ce3fa2c632e808e804637a1a) The ceph_on_in_msg_alloc() method drops con->mutex while it allocates a message. If that races with a timeout that resends a zillion messages and resets the connection, and the ->alloc_msg() method returns a NULL message, it will call ceph_msg_put(NULL) and BUG. Fix by only calling put if msg is non-NULL. Fixes http://tracker.newdream.net/issues/3142 Signed-off-by: Sage Weil Signed-off-by: Greg Kroah-Hartman --- net/ceph/messenger.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2746,7 +2746,8 @@ static int ceph_con_in_msg_alloc(struct 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;