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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,USER_AGENT_MUTT 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 69285C43441 for ; Mon, 12 Nov 2018 02:57:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E5041208A3 for ; Mon, 12 Nov 2018 02:57:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E5041208A3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730349AbeKLMsE (ORCPT ); Mon, 12 Nov 2018 07:48:04 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55032 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729769AbeKLMsD (ORCPT ); Mon, 12 Nov 2018 07:48:03 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id ED2D781DE9; Mon, 12 Nov 2018 02:56:59 +0000 (UTC) Received: from ming.t460p (ovpn-8-21.pek2.redhat.com [10.72.8.21]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 4506819940; Mon, 12 Nov 2018 02:56:53 +0000 (UTC) Date: Mon, 12 Nov 2018 10:56:48 +0800 From: Ming Lei To: Tetsuo Handa Cc: axboe@kernel.dk, Jan Kara , syzbot , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: WARNING: locking bug in loop_control_ioctl Message-ID: <20181112025647.GC21443@ming.t460p> References: <00000000000026aaac057a40a183@google.com> <913c3703-f6d3-a412-3b0c-ebc7422e8e69@I-love.SAKURA.ne.jp> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <913c3703-f6d3-a412-3b0c-ebc7422e8e69@I-love.SAKURA.ne.jp> User-Agent: Mutt/1.9.1 (2017-09-22) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.25]); Mon, 12 Nov 2018 02:57:00 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 10, 2018 at 05:09:09PM +0900, Tetsuo Handa wrote: > From 4b9e5556fada37dff1eff13665a229b69e1f7dd8 Mon Sep 17 00:00:00 2001 > From: Tetsuo Handa > Date: Sat, 10 Nov 2018 17:04:40 +0900 > Subject: [PATCH] loop: Fix double mutex_unlock(&loop_ctl_mutex) in loop_control_ioctl(). > > Commit 0a42e99b58a20883 ("loop: Get rid of loop_index_mutex") forgot to > remove mutex_unlock(&loop_ctl_mutex) from loop_control_ioctl() when > replacing loop_index_mutex with loop_ctl_mutex. > > Reported-by: syzbot > Signed-off-by: Tetsuo Handa > Cc: Jan Kara > --- > drivers/block/loop.c | 2 -- > 1 file changed, 2 deletions(-) > > diff --git a/drivers/block/loop.c b/drivers/block/loop.c > index bf6bc35..176ab1f 100644 > --- a/drivers/block/loop.c > +++ b/drivers/block/loop.c > @@ -2074,12 +2074,10 @@ static long loop_control_ioctl(struct file *file, unsigned int cmd, > break; > if (lo->lo_state != Lo_unbound) { > ret = -EBUSY; > - mutex_unlock(&loop_ctl_mutex); > break; > } > if (atomic_read(&lo->lo_refcnt) > 0) { > ret = -EBUSY; > - mutex_unlock(&loop_ctl_mutex); > break; > } > lo->lo_disk->private_data = NULL; > -- > 1.8.3.1 > Reviewed-by: Ming Lei -- Ming