From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Liu Subject: [PATCH v2] RDS: fix rds-ping spinlock recursion Date: Tue, 09 Oct 2012 12:57:27 +0800 Message-ID: <5073AEB7.9060309@oracle.com> Reply-To: jeff.liu@oracle.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Venkat Venkatsubra , davem@davemloft.net, Dan Carpenter , James Morris , netdev@vger.kernel.org To: rds-devel@oss.oracle.com Return-path: Received: from acsinet15.oracle.com ([141.146.126.227]:22788 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750952Ab2JIE6o (ORCPT ); Tue, 9 Oct 2012 00:58:44 -0400 Sender: netdev-owner@vger.kernel.org List-ID: Hello, This is the revised patch for fixing rds-ping spinlock recursion according to Venkat's suggestions. RDS ping/pong over TCP feature has been broken for years(2.6.39 to 3.6.0) since we have to set TCP cork and call kernel_sendmsg() between ping/pong which both need to lock "struct sock *sk". However, this lock has already been hold before rds_tcp_data_ready() callback is triggerred. As a result, we always facing spinlock resursion which would resulting in system panic. Given that RDS ping is only used to test the connectivity and not for serious performance measurements, we can queue the pong transmit to rds_wq as a delayed response. Reported-by: Dan Carpenter CC: Venkat Venkatsubra CC: David S. Miller CC: James Morris Signed-off-by: Jie Liu --- net/rds/send.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/rds/send.c b/net/rds/send.c index 96531d4..88eace5 100644 --- a/net/rds/send.c +++ b/net/rds/send.c @@ -1122,7 +1122,7 @@ rds_send_pong(struct rds_connection *conn, __be16 dport) rds_stats_inc(s_send_pong); if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags)) - rds_send_xmit(conn); + queue_delayed_work(rds_wq, &conn->c_send_w, 0); rds_message_put(rm); return 0; -- 1.7.9.5