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From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>,
	David Miller <davem@davemloft.net>,
	isdn@linux-pingi.de, arnd@arndb.de, edumazet@google.com,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	andrianov@ispras.ru, ldv-project@linuxtesting.org
Subject: Re: [PATCH] drivers: isdn: capi: Fix data-race bug
Date: Fri, 24 Jul 2020 20:28:35 +0530	[thread overview]
Message-ID: <20200724145835.GA30994@madhuparna-HP-Notebook> (raw)
In-Reply-To: <20200724065747.GF3880088@kroah.com>

On Fri, Jul 24, 2020 at 08:57:47AM +0200, Greg KH wrote:
> On Fri, Jul 24, 2020 at 10:18:07AM +0530, Madhuparna Bhowmik wrote:
> > On Thu, Jul 23, 2020 at 03:11:58PM -0700, David Miller wrote:
> > > From: madhuparnabhowmik10@gmail.com
> > > Date: Wed, 22 Jul 2020 22:53:29 +0530
> > > 
> > > > From: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
> > > > 
> > > > In capi_init(), after register_chrdev() the file operation callbacks
> > > > can be called. However capinc_tty_init() is called later.
> > > > Since capiminors and capinc_tty_driver are initialized in
> > > > capinc_tty_init(), their initialization can race with their usage
> > > > in various callbacks like in capi_release().
> > > > 
> > > > Therefore, call capinc_tty_init() before register_chrdev to avoid
> > > > such race conditions.
> > > > 
> > > > Found by Linux Driver Verification project (linuxtesting.org).
> > > > 
> > > > Signed-off-by: Madhuparna Bhowmik <madhuparnabhowmik10@gmail.com>
> > > 
> > > I agree with Arnd that this just exchanges one set of problems for
> > > another.
> > 
> > Thanks Arnd and David, for reviewing the patch.
> > Do you have any suggestions on how to fix this correctly?
> 
> Based on the installed base of ISDN systems, and the fact that no one
> has ever actually hit this race and reported it ever, I wouldn't worry
> about it :)
>
Fair enough! Thanks for having a look.

Regards,
Madhuparna

> thanks,
> 
> greg k-h

      reply	other threads:[~2020-07-24 14:58 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-22 17:23 madhuparnabhowmik10
2020-07-22 18:41 ` Arnd Bergmann
2020-07-23 22:11 ` David Miller
2020-07-24  4:48   ` Madhuparna Bhowmik
2020-07-24  6:57     ` Greg KH
2020-07-24 14:58       ` Madhuparna Bhowmik [this message]

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