Re: KASAN: slab-out-of-bounds Read in vhci_hub_control

[Dmitry Vyukov]

On Wed, Oct 10, 2018 at 10:26 PM, Shuah Khan <shuah@xxxxxxxxxx> wrote:
> On 10/10/2018 01:42 PM, Dmitry Vyukov wrote:
>> On Tue, Oct 2, 2018 at 6:04 PM, Shuah Khan <shuah@xxxxxxxxxx> wrote:
>>> On 09/04/2018 12:52 PM, syzbot wrote:
>>>> Hello,
>>>>
>>>> syzbot found the following crash on:
>>>>
>>>> HEAD commit:    420f51f4ab6b Merge tag 'arm64-fixes' of git://git.kernel.o..
>>>> git tree:       upstream
>>>> console output: https://syzkaller.appspot.com/x/log.txt?x=126a6f0e400000
>>>> kernel config:  https://syzkaller.appspot.com/x/.config?x=531a917630d2a492
>>>> dashboard link: https://syzkaller.appspot.com/bug?extid=bccc1fe10b70fadc78d0
>>>> compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
>>>> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=121caa46400000
>>>> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14ed8ab6400000
>>>
>>> C producer doesn't reproduce the problem on 4.19-rc5. Does this C producer
>>> depend on state of the machine? i.e what is the status of vhci_hcd - are
>>> there any devices attached?
>>>
>>> I can see the problem looking at the code and fix is easy. However, I would
>>> like be able to reproduce it and verify the fix works. Also this would be a
>>> good regression for the driver I could consider adding to selftests.
>>
>>
>>
>> Are you sure you used the provided config/commit?
>> I've followed these instructions:
>> https://github.com/google/syzkaller/blob/master/docs/syzbot.md#crash-does-not-reproduce
>> and the C repro gave me this in a second:
>
> I managed to reproduce and fix it. I did add reported by tag as well.
>
> Here is fix:
> https://patchwork.kernel.org/patch/10628833/
>
> Sudip verified the patch.

Great. Thanks!