Re: tty crash in Linux 4.6

[Mikulas Patocka]

On Sat, 16 Nov 2019, Greg Kroah-Hartman wrote:

> On Fri, Nov 15, 2019 at 11:21:08AM -0800, Mike Kravetz wrote:
> > On 4/11/18 9:09 AM, Daniel Axtens wrote:
> > > Mikulas Patocka <mpatocka@xxxxxxxxxx> writes:
> > > 
> > >> On Thu, 22 Mar 2018, Greg Kroah-Hartman wrote:
> > >>
> > >>> On Fri, Mar 23, 2018 at 12:48:06AM +1100, Daniel Axtens wrote:
> > >>>> Hi,
> > >>>>
> > >>>>>> This patch works, I've had no tty crashes since applying it.
> > >>>>>>
> > >>>>>> I've seen that you haven't sent this patch yet to Linux-4.7-rc and
> > >>>>>> Linux-4.6-stable. Will you? Or did you create a different patch?
> > >>>>>
> > >>>>> We are hitting this now on powerpc.  This patch never seemed to make
> > >>>>> it upstream (drivers/tty/tty_ldisc.c hasn't been touched in 1 year).
> > >>>>
> > >>>> I seem to be hitting this too on a kernel that has the 4.6 changes
> > >>>> backported to 4.4.
> > >>>>
> > >>>> Has there been any further progress on getting this accepted?
> > >>>
> > >>> Can you try applying 28b0f8a6962a ("tty: make n_tty_read() always abort
> > >>> if hangup is in progress") to see if that helps out or not?
> > > 
> > > Sorry for the delay in getting the test results; as with Mikulas,
> > > 28b0f8a6962a does not help.
> > > 
> > > Regards,
> > > Daniel
> > > 
> > >>>
> > >>> thanks,
> > >>>
> > >>> greg k-h
> > >>
> > >> It doesn't help. I get the same crash as before.
> > >>
> > >> Mikulas
> > 
> > Reviving a really old thread.
> > 
> > It looks like this patch never got merged.
> 
> I do not see a patch in this email, so I have no idea what you are
> referring to, sorry.
> 
> > Did it get resolved in some other way?  I ask because we have a
> > customer who seems to have hit this issue.
> 
> Can you try with the latest kernel to see if it is resolved or not?

I tested it on the kernel 5.4 and I couldn't reproduce the crash anymore.

Mikulas

> thanks,
> 
> greg k-h
>