Re: general protection fault in n_tty_receive_buf_common

[Dmitry Vyukov]

On Fri, Oct 27, 2017 at 11:33 AM, Jiri Slaby <jslaby@xxxxxxx> wrote:
> On 10/27/2017, 11:24 AM, Dmitry Vyukov wrote:
>> On Fri, Oct 27, 2017 at 11:22 AM, syzbot
>> <bot+7fde9fa6e982d17b9acf978961e059b0a5344719@xxxxxxxxxxxxxxxxxxxxxxxxx>
>> wrote:
>>> Hello,
>>>
>>> syzkaller hit the following crash on
>>> 623ce3456671ea842c0ebda79c38655c8c04af74
>>> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master
>>> compiler: gcc (GCC) 7.1.1 20170620
>>> .config is attached
>>> Raw console output is attached.
>>
>> A more recent report is on upstream 0787643a5f6aad1f0cdeb305f7fe492b71943ea4
>
> Bad. Do we have a reproducer?

Please refer to this section of the referenced doc:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#no-reproducer-at-all

In this case we don't even know what program from the log triggered
it, because the crash happened in the background thread. Probably one
of the programs doing openat$ptmx.
And we only got 30 of such crashes overall, so it seems to be
notoriously difficult to reproduce.