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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 044F5C2BA83 for ; Thu, 13 Feb 2020 15:35:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CA50D20675 for ; Thu, 13 Feb 2020 15:35:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728869AbgBMPfF (ORCPT ); Thu, 13 Feb 2020 10:35:05 -0500 Received: from mx2.suse.de ([195.135.220.15]:37682 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388141AbgBMPcK (ORCPT ); Thu, 13 Feb 2020 10:32:10 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id 1D1E3B137; Thu, 13 Feb 2020 15:32:09 +0000 (UTC) From: Hannes Reinecke To: "Martin K. Petersen" Cc: Christoph Hellwig , Bart van Assche , James Bottomley , linux-scsi@vger.kernel.org, Hannes Reinecke Subject: [PATCH 2/3] ch: synchronize ch_probe() and ch_open() Date: Thu, 13 Feb 2020 16:32:06 +0100 Message-Id: <20200213153207.123357-3-hare@suse.de> X-Mailer: git-send-email 2.16.4 In-Reply-To: <20200213153207.123357-1-hare@suse.de> References: <20200213153207.123357-1-hare@suse.de> Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org The 'ch' device node is created before the configuration is being read in, which leads to a race window when ch_open() is called before that. To avoid any races we should be taking the device mutex during ch_readconfig() and ch_init_elem(), and also during ch_open(). That ensures ch_probe is finished before ch_open() completes. Signed-off-by: Hannes Reinecke --- drivers/scsi/ch.c | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/ch.c b/drivers/scsi/ch.c index 974afb4bd5fe..9cbfb00ab950 100644 --- a/drivers/scsi/ch.c +++ b/drivers/scsi/ch.c @@ -606,7 +606,10 @@ ch_open(struct inode *inode, struct file *file) mutex_unlock(&ch_mutex); return -ENXIO; } + /* Synchronize with ch_probe() */ + mutex_lock(&ch->lock); file->private_data = ch; + mutex_unlock(&ch->lock); mutex_unlock(&ch_mutex); return 0; } @@ -949,6 +952,9 @@ static int ch_probe(struct device *dev) goto remove_idr; } + mutex_init(&ch->lock); + kref_init(&ch->ref); + ch->device = sd; class_dev = device_create(ch_sysfs_class, dev, MKDEV(SCSI_CHANGER_MAJOR, ch->minor), ch, "s%s", ch->name); @@ -959,15 +965,16 @@ static int ch_probe(struct device *dev) goto put_device; } - mutex_init(&ch->lock); - kref_init(&ch->ref); - ch->device = sd; + mutex_lock(&ch->lock); ret = ch_readconfig(ch); - if (ret) + if (ret) { + mutex_unlock(&ch->lock); goto destroy_dev; + } if (init) ch_init_elem(ch); + mutex_unlock(&ch->lock); dev_set_drvdata(dev, ch); sdev_printk(KERN_INFO, sd, "Attached scsi changer %s\n", ch->name); -- 2.16.4