From: Greg KH <gregkh@linuxfoundation.org>
To: Ming Lei <ming.lei@canonical.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Wedson Almeida Filho <wedsonaf@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org,
Linux PM List <linux-pm@vger.kernel.org>
Subject: Re: Race condition between driver_probe_device and device_shutdown
Date: Wed, 23 May 2012 19:14:29 -0700 [thread overview]
Message-ID: <20120524021429.GB12557@kroah.com> (raw)
In-Reply-To: <CACVXFVMqWyT78h53WnLuMYuhfFK-sbGMkS+T8SjWad6kQVFGTw@mail.gmail.com>
On Thu, May 24, 2012 at 09:39:46AM +0800, Ming Lei wrote:
> On Wed, May 23, 2012 at 11:06 PM, Alan Stern <stern@rowland.harvard.edu> wrote:
> > On Wed, 23 May 2012, Ming Lei wrote:
> >> The .shutdown callback pointer is got from device->driver, which is
> >> changed in probe and release path. Also runtime PM thing has been
> >> involved into shutting down recently, so looks not only hardware parts
> >> are involved now.
> >
> > This is a tricky question. Overall I think you're probably right.
> >
> > It's certainly true that holding the device lock across the shutdown
> > callback is the easiest and most reliable way to prevent these races.
>
> But holding device lock across .shutdown is very inefficient because
> most of devices' driver have not shutdown callback, so I think it is better
> to fix the race by prevent driver core from probing or releasing once
> shutdown is started.
>
> How about the below patch?
How about waiting for the original poster to respond as to exactly how
they are hitting this race before doing anything?
greg k-h
next prev parent reply other threads:[~2012-05-24 2:14 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-05-18 4:59 Greg KH
2012-05-20 14:08 ` Ming Lei
2012-05-20 19:51 ` Greg KH
2012-05-21 4:53 ` Ming Lei
2012-05-21 18:29 ` Alan Stern
2012-05-22 0:35 ` Ming Lei
2012-05-22 14:11 ` Alan Stern
2012-05-22 19:16 ` Eric W. Biederman
2012-05-23 10:05 ` Ming Lei
2012-05-23 15:06 ` Alan Stern
2012-05-24 1:39 ` Ming Lei
2012-05-24 2:14 ` Greg KH [this message]
2012-05-24 3:12 ` Ming Lei
2012-05-24 14:37 ` Alan Stern
2012-05-25 0:33 ` Ming Lei
2012-12-06 9:11 ` Race condition between driver_probe_device and device_shutdown Wedson Almeida Filho
2012-12-06 10:52 ` Ming Lei
2012-12-07 0:09 ` Wedson Almeida Filho
2012-12-07 3:42 ` Ming Lei
2012-12-07 12:16 ` Wedson Almeida Filho
2012-12-07 13:04 ` Ming Lei
2012-12-07 15:25 ` Alan Stern
2012-12-07 16:27 ` Ming Lei
-- strict thread matches above, loose matches on Subject: below --
2012-05-10 2:53 Race condition between driver_probe_device and device_shutdown Wedson Almeida Filho
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