From: Kyungtae Kim <kt0755@gmail.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: William Hubbs <w.d.hubbs@gmail.com>,
Christopher Brannon <chris@the-brannons.com>,
kirk@reisers.ca, Samuel Thibault <samuel.thibault@ens-lyon.org>,
Byoungyoung Lee <lifeasageek@gmail.com>,
DaeRyong Jeong <threeearcat@gmail.com>,
speakup@linux-speakup.org, devel@driverdev.osuosl.org,
linux-kernel@vger.kernel.org, syzkaller@googlegroups.com
Subject: Re: general protection fault in spk_ttyio_ldisc_close
Date: Tue, 8 Jan 2019 09:15:02 -0500 [thread overview]
Message-ID: <CAEAjamuyjcxVNF5seJ0w0LQT0FSqvHYG30fzhe1s7UgVWzdaFg@mail.gmail.com> (raw)
In-Reply-To: <20190108135020.GA10504@kroah.com>
On Tue, Jan 8, 2019 at 8:50 AM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Tue, Jan 08, 2019 at 08:37:37AM -0500, Kyungtae Kim wrote:
> > We report a bug in linux-4.20: "general protection fault in
> > spk_ttyio_ldisc_close"
> >
> > kernel config: https://kt0755.github.io/etc/config_v4.20_stable
> > repro: https://kt0755.github.io/etc/repro.a670e.c
> >
> > This occurs when the function kfree is about to execute
> > (driver/staging/speakup/spk_ttyio.c:68).
> > Particularly, kfree takes the argument like speakup_tty->disc_data.
> > But speakup_tty is invalid, so the pointer dereference causes GPF.
> > At a glance, it seems that speakup_tty was deallocated somewhere ahead of kfree.
>
> How did you trigger this? Did you shut down and close the device
> already somehow? Do you have a real tty device that is driven by the
> device?
>
> thanks,
>
> greg k-h
For this crash, we did without real speakup tty device.
I'm currently trying to figure out how this actually happens.
Thanks,
Kyungtae Kim
next prev parent reply other threads:[~2019-01-08 14:15 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-08 13:37 general protection fault in spk_ttyio_ldisc_close Kyungtae Kim
2019-01-08 13:50 ` Greg KH
2019-01-08 14:15 ` Kyungtae Kim [this message]
2019-01-08 14:25 ` Greg KH
2019-01-08 14:26 ` Samuel Thibault
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