From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 In-Reply-To: <913c3703-f6d3-a412-3b0c-ebc7422e8e69@I-love.SAKURA.ne.jp> List-ID: 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