From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:36334 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727175AbfKVF5s (ORCPT ); Fri, 22 Nov 2019 00:57:48 -0500 From: Sasha Levin Subject: [PATCH AUTOSEL 4.14 108/127] net/smc: prevent races between smc_lgr_terminate() and smc_conn_free() Date: Fri, 22 Nov 2019 00:55:26 -0500 Message-Id: <20191122055544.3299-107-sashal@kernel.org> In-Reply-To: <20191122055544.3299-1-sashal@kernel.org> References: <20191122055544.3299-1-sashal@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-s390-owner@vger.kernel.org List-ID: To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Karsten Graul , Ursula Braun , "David S . Miller" , Sasha Levin , linux-s390@vger.kernel.org, netdev@vger.kernel.org From: Karsten Graul [ Upstream commit 77f838ace755d2f466536c44dac6c856f62cd901 ] To prevent races between smc_lgr_terminate() and smc_conn_free() add an extra check of the lgr field before accessing it, and cancel a delayed free_work when a new smc connection is created. This fixes the problem that free_work cleared the lgr variable but smc_lgr_terminate() or smc_conn_free() still access it in parallel. Signed-off-by: Karsten Graul Signed-off-by: Ursula Braun Signed-off-by: David S. Miller Signed-off-by: Sasha Levin --- net/smc/smc_core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/smc/smc_core.c b/net/smc/smc_core.c index f04a037dc9677..0de788fa43e95 100644 --- a/net/smc/smc_core.c +++ b/net/smc/smc_core.c @@ -103,6 +103,8 @@ static void smc_lgr_unregister_conn(struct smc_connection *conn) struct smc_link_group *lgr = conn->lgr; int reduced = 0; + if (!lgr) + return; write_lock_bh(&lgr->conns_lock); if (conn->alert_token_local) { reduced = 1; @@ -431,6 +433,8 @@ int smc_conn_create(struct smc_sock *smc, __be32 peer_in_addr, local_contact = SMC_REUSE_CONTACT; conn->lgr = lgr; smc_lgr_register_conn(conn); /* add smc conn to lgr */ + if (delayed_work_pending(&lgr->free_work)) + cancel_delayed_work(&lgr->free_work); write_unlock_bh(&lgr->conns_lock); break; } -- 2.20.1