From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 146D2C352BE for ; Thu, 16 Apr 2020 15:36:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E3DEF214AF for ; Thu, 16 Apr 2020 15:36:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587051413; bh=Myj1CDp0UdOsG9VN9HTP9WtLs++9igsmwDL49tx1CsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=2FlrIyopqCUzMBB82b82PIlVDTyO7nxnhecgrJJtH+4WdFsvidm7ehC9f26n/aySx 5KULD6PFqqLitbKNEFpcbjLg1vHwGeyHt8GW8MSpmJzSQY6mrLYiMD5aeOkUDnHsIB Ev99rPyvuf3ZElumioCUOx7bj4vxrruVUD3b2X58= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2441598AbgDPPgw (ORCPT ); Thu, 16 Apr 2020 11:36:52 -0400 Received: from mail.kernel.org ([198.145.29.99]:52204 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2897880AbgDPNjp (ORCPT ); Thu, 16 Apr 2020 09:39:45 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 999252063A; Thu, 16 Apr 2020 13:39:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1587044385; bh=Myj1CDp0UdOsG9VN9HTP9WtLs++9igsmwDL49tx1CsU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=XydSTFfOL1+RT1TqtAdKPT8CqaQXCWhz+gCSJgf8YBf++rJBML8boiRAPFyM+8tyk /nrL1Y6DKMBkSXIxJX9oND5VD430G4iE1rUAZ8xkmij/o4lH7bFqi18VX/m7/kTXoK pwbP/a2PCHuc3siaE9xd2BADrBuE1QElv/nwz1ho= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jens Remus , Benjamin Block , Steffen Maier , "Martin K. Petersen" Subject: [PATCH 5.5 195/257] scsi: zfcp: fix missing erp_lock in port recovery trigger for point-to-point Date: Thu, 16 Apr 2020 15:24:06 +0200 Message-Id: <20200416131350.576747147@linuxfoundation.org> X-Mailer: git-send-email 2.26.1 In-Reply-To: <20200416131325.891903893@linuxfoundation.org> References: <20200416131325.891903893@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Steffen Maier commit 819732be9fea728623e1ed84eba28def7384ad1f upstream. v2.6.27 commit cc8c282963bd ("[SCSI] zfcp: Automatically attach remote ports") introduced zfcp automatic port scan. Before that, the user had to use the sysfs attribute "port_add" of an FCP device (adapter) to add and open remote (target) ports, even for the remote peer port in point-to-point topology. That code path did a proper port open recovery trigger taking the erp_lock. Since above commit, a new helper function zfcp_erp_open_ptp_port() performed an UNlocked port open recovery trigger. This can race with other parallel recovery triggers. In zfcp_erp_action_enqueue() this could corrupt e.g. adapter->erp_total_count or adapter->erp_ready_head. As already found for fabric topology in v4.17 commit fa89adba1941 ("scsi: zfcp: fix infinite iteration on ERP ready list"), there was an endless loop during tracing of rport (un)block. A subsequent v4.18 commit 9e156c54ace3 ("scsi: zfcp: assert that the ERP lock is held when tracing a recovery trigger") introduced a lockdep assertion for that case. As a side effect, that lockdep assertion now uncovered the unlocked code path for PtP. It is from within an adapter ERP action: zfcp_erp_strategy[1479] intentionally DROPs erp lock around zfcp_erp_strategy_do_action() zfcp_erp_strategy_do_action[1441] NO erp lock zfcp_erp_adapter_strategy[876] NO erp lock zfcp_erp_adapter_strategy_open[855] NO erp lock zfcp_erp_adapter_strategy_open_fsf[806]NO erp lock zfcp_erp_adapter_strat_fsf_xconf[772] erp lock only around zfcp_erp_action_to_running(), BUT *_not_* around zfcp_erp_enqueue_ptp_port() zfcp_erp_enqueue_ptp_port[728] BUG: *_not_* taking erp lock _zfcp_erp_port_reopen[432] assumes to be called with erp lock zfcp_erp_action_enqueue[314] assumes to be called with erp lock zfcp_dbf_rec_trig[288] _checks_ to be called with erp lock: lockdep_assert_held(&adapter->erp_lock); It causes the following lockdep warning: WARNING: CPU: 2 PID: 775 at drivers/s390/scsi/zfcp_dbf.c:288 zfcp_dbf_rec_trig+0x16a/0x188 no locks held by zfcperp0.0.17c0/775. Fix this by using the proper locked recovery trigger helper function. Link: https://lore.kernel.org/r/20200312174505.51294-2-maier@linux.ibm.com Fixes: cc8c282963bd ("[SCSI] zfcp: Automatically attach remote ports") Cc: #v2.6.27+ Reviewed-by: Jens Remus Reviewed-by: Benjamin Block Signed-off-by: Steffen Maier Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/s390/scsi/zfcp_erp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/s390/scsi/zfcp_erp.c +++ b/drivers/s390/scsi/zfcp_erp.c @@ -725,7 +725,7 @@ static void zfcp_erp_enqueue_ptp_port(st adapter->peer_d_id); if (IS_ERR(port)) /* error or port already attached */ return; - _zfcp_erp_port_reopen(port, 0, "ereptp1"); + zfcp_erp_port_reopen(port, 0, "ereptp1"); } static enum zfcp_erp_act_result zfcp_erp_adapter_strat_fsf_xconf(