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=-6.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham 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 03132C169C4 for ; Mon, 11 Feb 2019 14:37:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C906C20700 for ; Mon, 11 Feb 2019 14:37:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549895838; bh=TyjVEQTUM45xJ027sF3TCc/yB1CnsZoueeFb47WgYTU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=r22BHdYLxRqBJ1vwrU5VJDV6w/d3uFaFU+L6khYLs0TfyzbwFy9s+oYXCmVJjvYeK 2sb7LVDgKg2IcLwkfGqK0CiApO8ZCdIKqlZtso7ErKcVgE1yyTnOMNUZAGDK9NC/4d 1TPtc3bPrMVCBUanEtK25yDjuV1mcMOvwNcrtdpg= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731419AbfBKOhR (ORCPT ); Mon, 11 Feb 2019 09:37:17 -0500 Received: from mail.kernel.org ([198.145.29.99]:46536 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730980AbfBKOhO (ORCPT ); Mon, 11 Feb 2019 09:37:14 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 723C221B18; Mon, 11 Feb 2019 14:37:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1549895833; bh=TyjVEQTUM45xJ027sF3TCc/yB1CnsZoueeFb47WgYTU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=bBxxncVYxQUHNOfZZHsdaKFaGhktONDBLGom2Y8MBXiEtQpF/cbg6twHeeMhLtRfz eEtG0561dTZDYNKgfJBN+JthxPXnXZiP3cki31sFGEjAaNr2guI9VQ079hDMvMCsEg 7Dt9WEmdmyUhBmR8atIoqu3m74twdDPZhM1Db9nc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Vaibhav Jain , "Martin K. Petersen" Subject: [PATCH 4.20 337/352] scsi: cxlflash: Prevent deadlock when adapter probe fails Date: Mon, 11 Feb 2019 15:19:24 +0100 Message-Id: <20190211141908.563842445@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190211141846.543045703@linuxfoundation.org> References: <20190211141846.543045703@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ From: Vaibhav Jain commit bb61b843ffd46978d7ca5095453e572714934eeb upstream. Presently when an error is encountered during probe of the cxlflash adapter, a deadlock is seen with cpu thread stuck inside cxlflash_remove(). Below is the trace of the deadlock as logged by khungtaskd: cxlflash 0006:00:00.0: cxlflash_probe: init_afu failed rc=-16 INFO: task kworker/80:1:890 blocked for more than 120 seconds. Not tainted 5.0.0-rc4-capi2-kexec+ #2 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. kworker/80:1 D 0 890 2 0x00000808 Workqueue: events work_for_cpu_fn Call Trace: 0x4d72136320 (unreliable) __switch_to+0x2cc/0x460 __schedule+0x2bc/0xac0 schedule+0x40/0xb0 cxlflash_remove+0xec/0x640 [cxlflash] cxlflash_probe+0x370/0x8f0 [cxlflash] local_pci_probe+0x6c/0x140 work_for_cpu_fn+0x38/0x60 process_one_work+0x260/0x530 worker_thread+0x280/0x5d0 kthread+0x1a8/0x1b0 ret_from_kernel_thread+0x5c/0x80 INFO: task systemd-udevd:5160 blocked for more than 120 seconds. The deadlock occurs as cxlflash_remove() is called from cxlflash_probe() without setting 'cxlflash_cfg->state' to STATE_PROBED and the probe thread starts to wait on 'cxlflash_cfg->reset_waitq'. Since the device was never successfully probed the 'cxlflash_cfg->state' never changes from STATE_PROBING hence the deadlock occurs. We fix this deadlock by setting the variable 'cxlflash_cfg->state' to STATE_PROBED in case an error occurs during cxlflash_probe() and just before calling cxlflash_remove(). Cc: stable@vger.kernel.org Fixes: c21e0bbfc485("cxlflash: Base support for IBM CXL Flash Adapter") Signed-off-by: Vaibhav Jain Signed-off-by: Martin K. Petersen Signed-off-by: Greg Kroah-Hartman --- drivers/scsi/cxlflash/main.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/scsi/cxlflash/main.c +++ b/drivers/scsi/cxlflash/main.c @@ -3694,6 +3694,7 @@ static int cxlflash_probe(struct pci_dev host->max_cmd_len = CXLFLASH_MAX_CDB_LEN; cfg = shost_priv(host); + cfg->state = STATE_PROBING; cfg->host = host; rc = alloc_mem(cfg); if (rc) { @@ -3782,6 +3783,7 @@ out: return rc; out_remove: + cfg->state = STATE_PROBED; cxlflash_remove(pdev); goto out; }