Re: [PATCH v3 0/2] vhost fixes for OVS SIGSEGV in PMD

[Claudio Fontana <cfontana@suse.de>]

On 8/2/22 19:20, Claudio Fontana wrote:
> On 8/2/22 03:40, Stephen Hemminger wrote:
>> On Tue,  2 Aug 2022 02:49:36 +0200
>> Claudio Fontana <cfontana@suse.de> wrote:
>>
>>> This is an alternative, more general fix compared with PATCH v1,
>>> and fixes style issues in v2.
>>>
>>> The series fixes a segmentation fault in the OVS PMD thread when
>>> resynchronizing with QEMU after the guest application has been killed
>>> with SIGKILL (patch 1/2),
>>>
>>> The segmentation fault can be caused by the guest DPDK application,
>>> which is able this way to crash the OVS process on the host,
>>> see the backtrace in patch 1/2.
>>>
>>> Patch 2/2 is an additional improvement in the current error handling.
>>
>> Checking for NULL and 0 is good on host side.
>> But guest should probably not be sending such a useless request?
> 
> 
> Right, I focused on hardening the host side, as that is what the customer required.
> 
> This happens specifically when the guest application goes away abruptly and has no chance to signal anything (SIGKILL),
> and at restart issues a virtio reset on the device, which in qemu causes also a (actually two) virtio_net set_status, which attempt to stop the queues (twice).
> 
> DPDK seems to think at that point that it needs to drain the queue, and tries to process MAX_PKT_BURST buffers
> ("about to dequeue 32 buffers"),
> 
> then calls fill_vec_buf_split and gets absolutely nothing.
> 
> I think this should also address the reports in this thread:
> 
> https://inbox.dpdk.org/dev/SA1PR08MB713373B0D19329C38C7527BB839A9@SA1PR08MB7133.namprd08.prod.outlook.com/
> 
> in addition to my specific customer request,
> 
> Thanks,
> 
> Claudio

anything more required from my side? Do you need a respin without the "Tested-by" tag?

Thanks,

Claudio