From: Greg KH <gregkh@linuxfoundation.org>
To: Dmitry Vyukov <dvyukov@google.com>
Cc: Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
Vegard Nossum <vegard.nossum@gmail.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Jiri Slaby <jslaby@suse.cz>,
Andrew Morton <akpm@linux-foundation.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-serial <linux-serial@vger.kernel.org>
Subject: Re: [GIT PULL] TTY/Serial driver fixes for 4.11-rc4
Date: Fri, 2 Jun 2017 09:06:33 +0900 [thread overview]
Message-ID: <20170602000633.GA3058@kroah.com> (raw)
In-Reply-To: <CACT4Y+YSOD26=AAMgw2D-A_Nvk5On71qLY40LhXXUiZpp2-h+Q@mail.gmail.com>
On Thu, Jun 01, 2017 at 02:06:08PM +0200, Dmitry Vyukov wrote:
> On Wed, May 31, 2017 at 5:04 PM, Alan Cox <gnomes@lxorguk.ukuu.org.uk> wrote:
> > On Wed, 31 May 2017 20:16:12 +0900
> > Greg KH <gregkh@linuxfoundation.org> wrote:
> >
> >> On Wed, May 31, 2017 at 10:39:23AM +0200, Dmitry Vyukov wrote:
> >> > On Tue, May 30, 2017 at 2:09 PM, Alan Cox <gnomes@lxorguk.ukuu.org.uk> wrote:
> >> > >> >> I'll think about possible solutions, but I have no prior experience
> >> > >> >> with the tty code. In the meantime syzkaller also hit a couple of
> >> > >> >> other fun tty/pty bugs including a write/ioctl race that results in
> >> > >> >> buffer overflow :-/
> >> > >
> >> > > There are several of those, including some of that have been documented
> >> > > for years but nobody ever volunteered to fix - in particular all the
> >> > > interfaces that push characters to the tty other than via the normal
> >> > > interrupt receive path are dodgy (console selection in particular)
> >> > >
> >> > > The original tty model btw was that setting the ldisc to n_tty cannot
> >> > > fail, and the structure allocated was smaller than a page size so was
> >> > > safe.
> >> > >
> >> > > The simple way to fix it is to restore that behaviour by adding a 'null'
> >> > > ldisc that we can fail to instead of N_TTY since the N_TTY failback path
> >> > > is long broken.
> >> >
> >> > Greg, what do you think about this patch? Are you ready to accept
> >> > something like this?
> >> > Definitely shorter than changing all drivers.
> >>
> >> Yes, it looks reasonable to me.
> >
> >
> >
> > Ok try this
>
>
> I've applied the patch and run syzkaller with it. I don't see kernel
> panics in tty_ldisc_restore any more. Also don't see any new
> tty-related crashes.
>
> Greg, will you take it from here?
I can if Alan sends it to me in a form I can apply it in (i.e. it has a
siged-off-by line...)
thanks,
greg k-h
prev parent reply other threads:[~2017-06-02 0:06 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-26 11:04 [GIT PULL] TTY/Serial driver fixes for 4.11-rc4 Greg KH
2017-04-13 10:50 ` Vegard Nossum
2017-04-13 16:07 ` Linus Torvalds
2017-04-13 18:34 ` Greg KH
2017-04-14 9:41 ` Vegard Nossum
2017-04-14 12:30 ` Greg KH
2017-05-02 16:35 ` Dmitry Vyukov
2017-05-02 21:52 ` Vegard Nossum
2017-05-03 11:25 ` Dmitry Vyukov
2017-05-03 12:01 ` Greg KH
2017-05-30 9:21 ` Dmitry Vyukov
2017-05-30 12:09 ` Alan Cox
2017-05-31 8:39 ` Dmitry Vyukov
2017-05-31 11:16 ` Greg KH
2017-05-31 15:04 ` Alan Cox
2017-06-01 12:06 ` Dmitry Vyukov
2017-06-02 0:06 ` Greg KH [this message]
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