From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Return-Path: Date: Tue, 25 Apr 2017 15:30:23 -0700 From: Omar Sandoval To: Bart Van Assche Cc: "linux-block@vger.kernel.org" , "axboe@kernel.dk" Subject: Re: [PATCH v5 05/10] blk-mq: Unregister debugfs attributes earlier Message-ID: <20170425223023.GE6361@vader> References: <20170425203745.19946-1-bart.vanassche@sandisk.com> <20170425203745.19946-6-bart.vanassche@sandisk.com> <20170425213018.GB6361@vader> <1493159087.2628.28.camel@sandisk.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 In-Reply-To: <1493159087.2628.28.camel@sandisk.com> List-ID: On Tue, Apr 25, 2017 at 10:24:48PM +0000, Bart Van Assche wrote: > On Tue, 2017-04-25 at 14:30 -0700, Omar Sandoval wrote: > > On Tue, Apr 25, 2017 at 01:37:40PM -0700, Bart Van Assche wrote: > > > One of the debugfs attributes allows to run a queue. Since running > > > a queue after a queue has entered the "dead" state is not allowed > > > and triggers a use-after-free, unregister the debugfs attributes > > > before a queue reaches the "dead" state. > > > > Still not happy with this commit message. I'd prefer: > > > > We currently call blk_mq_free_queue() from blk_cleanup_queue() before we > > unregister the debugfs attributes for that queue in blk_release_queue(). > > This leaves a window open during which accessing most of the mq debugfs > > attributes would cause a use-after-free. Additionally, the "state" > > attribute allows running the queue, which we should not do after the > > queue has entered the "dead" state. Fix both of these cases by > > unregistering the debugfs attributes before this. > > Hello Omar, > > That's a very verbose description. How about this? > > ���Unregister the debugfs attributes before freeing of request queue > ����resources starts to avoid that a use-after-free can be triggered > ����through one of the debugfs attributes. > > Bart. Are you aware that there is nothing wrong with a descriptive commit message?