Re: general protection fault in tun_do_read

From: Dmitry Vyukov
Date: Fri Jan 26 2018 - 02:40:23 EST


On Fri, Jan 26, 2018 at 4:24 AM, Jason Wang <jasowang@xxxxxxxxxx> wrote:
>
>
> On 2018å01æ25æ 15:59, syzbot wrote:
>>
>> Hello,
>>
>> syzbot hit the following crash on net-next commit
>> 43df215d99e6049d4680309c54232689e16ddd6b (Wed Jan 24 01:24:32 2018 +0000)
>> Merge branch 'bpf-and-netdevsim-test-updates'
>>
>> So far this crash happened 2 times on net-next.
>> Unfortunately, I don't have any reproducer for this crash yet.
>> Raw console output is attached.
>> compiler: gcc (GCC) 7.1.1 20170620
>> .config is attached.
>>
>> IMPORTANT: if you fix the bug, please add the following tag to the commit:
>> Reported-by: syzbot+885a488f0e7e392e9022@xxxxxxxxxxxxxxxxxxxxxxxxx
>> It will help syzbot understand when the bug is fixed. See footer for
>> details.
>> If you forward the report, please keep this part and the footer.
>
>
> I suspect this is the same as what syzbot repots here
> https://www.spinics.net/lists/netdev/msg480736.html.
>
> We're discussing a solution posted by Michael here
> https://patchwork.ozlabs.org/patch/866064/

Thanks for notifying, Jason.
Let's also tell syzbot about this so that it will ever report bugs in
tun_do_read again:

#syz dup: general protection fault in tun_queue_purge