linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Arnd Bergmann <arnd@arndb.de>
To: madhuparnabhowmik10@gmail.com
Cc: Karsten Keil <isdn@linux-pingi.de>,
	David Miller <davem@davemloft.net>,
	gregkh <gregkh@linuxfoundation.org>,
	Eric Dumazet <edumazet@google.com>,
	Networking <netdev@vger.kernel.org>,
	"linux-kernel@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: Wed, 22 Jul 2020 20:41:23 +0200	[thread overview]
Message-ID: <CAK8P3a23zUHGnVBsBX=GqBzbRxwkqmOA_7heMze4EsyQvVfg3g@mail.gmail.com> (raw)
In-Reply-To: <20200722172329.16727-1-madhuparnabhowmik10@gmail.com>

On Wed, Jul 22, 2020 at 7:23 PM <madhuparnabhowmik10@gmail.com> wrote:
>
> 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 don't think there are any users of this driver, but I had a look anyway.

The patch looks reasonable at first, but I'm not sure if you just
replace one race with another, since now the tty device can be
opened before the rest of the subsystem is initialized.

It's probably fine.

         Arnd

  reply	other threads:[~2020-07-22 18:41 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 [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to='CAK8P3a23zUHGnVBsBX=GqBzbRxwkqmOA_7heMze4EsyQvVfg3g@mail.gmail.com' \
    --to=arnd@arndb.de \
    --cc=andrianov@ispras.ru \
    --cc=davem@davemloft.net \
    --cc=edumazet@google.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=isdn@linux-pingi.de \
    --cc=ldv-project@linuxtesting.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=madhuparnabhowmik10@gmail.com \
    --cc=netdev@vger.kernel.org \
    --subject='Re: [PATCH] drivers: isdn: capi: Fix data-race bug' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).