From: Greg KH <gregkh@linuxfoundation.org>
To: Kyungtae Kim <kt0755@gmail.com>
Cc: devel@driverdev.osuosl.org, kirk@reisers.ca,
speakup@linux-speakup.org, linux-kernel@vger.kernel.org,
syzkaller@googlegroups.com,
Byoungyoung Lee <lifeasageek@gmail.com>,
Samuel Thibault <samuel.thibault@ens-lyon.org>,
DaeRyong Jeong <threeearcat@gmail.com>,
Christopher Brannon <chris@the-brannons.com>
Subject: Re: general protection fault in spk_ttyio_ldisc_close
Date: Tue, 8 Jan 2019 15:25:07 +0100 [thread overview]
Message-ID: <20190108142507.GA13938@kroah.com> (raw)
In-Reply-To: <CAEAjamuyjcxVNF5seJ0w0LQT0FSqvHYG30fzhe1s7UgVWzdaFg@mail.gmail.com>
On Tue, Jan 08, 2019 at 09:15:02AM -0500, Kyungtae Kim wrote:
> 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.
How did you bind a non-real speakup tty device to the driver?
> I'm currently trying to figure out how this actually happens.
That would be great to figure out :)
thanks,
greg k-h
next prev parent reply other threads:[~2019-01-08 14:25 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
2019-01-08 14:25 ` Greg KH [this message]
2019-01-08 14:26 ` Samuel Thibault
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=20190108142507.GA13938@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=chris@the-brannons.com \
--cc=devel@driverdev.osuosl.org \
--cc=kirk@reisers.ca \
--cc=kt0755@gmail.com \
--cc=lifeasageek@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=samuel.thibault@ens-lyon.org \
--cc=speakup@linux-speakup.org \
--cc=syzkaller@googlegroups.com \
--cc=threeearcat@gmail.com \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).