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
prev parent 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 [PATCH] drivers: isdn: capi: Fix data-race bug 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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