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 , Alex Elder Subject: [ 158/171] libceph: avoid dropping con mutex before fault Date: Wed, 21 Nov 2012 16:41:44 -0800 Message-Id: <20121122004049.212668349@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 8636ea672f0c5ab7478c42c5b6705ebd1db7eb6a) The ceph_fault() function takes the con mutex, so we should avoid dropping it before calling it. This fixes a potential race with another thread calling ceph_con_close(), or _open(), or similar (we don't reverify con->state after retaking the lock). Add annotation so that lockdep realizes we will drop the mutex before returning. Signed-off-by: Sage Weil Reviewed-by: Alex Elder Signed-off-by: Greg Kroah-Hartman --- net/ceph/messenger.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) --- a/net/ceph/messenger.c +++ b/net/ceph/messenger.c @@ -2336,7 +2336,6 @@ done_unlocked: return; fault: - mutex_unlock(&con->mutex); ceph_fault(con); /* error/fault path */ goto done_unlocked; } @@ -2347,9 +2346,8 @@ fault: * exponential backoff */ static void ceph_fault(struct ceph_connection *con) + __releases(con->mutex) { - mutex_lock(&con->mutex); - pr_err("%s%lld %s %s\n", ENTITY_NAME(con->peer_name), ceph_pr_addr(&con->peer_addr.in_addr), con->error_msg); dout("fault %p state %lu to peer %s\n",