Re: [PATCH 4/6] usbip: fix stub_dev usbip_sockfd_store() races leading to gpf

[Shuah Khan <skhan@linuxfoundation.org>]

On 3/9/21 4:04 AM, Tetsuo Handa wrote:
> On 2021/03/09 1:27, Shuah Khan wrote:
>> Yes. We might need synchronization between events, threads, and shutdown
>> in usbip_host side and in connection polling and threads in vhci.
>>
>> I am also looking at the shutdown sequences closely as well since the
>> local state is referenced without usbip_device lock in these paths.
>>
>> I am approaching these problems as peeling the onion an expression so
>> we can limit the changes and take a spot fix approach. We have the
>> goal to address these crashes and not introduce regressions.
> 
> I think my [PATCH v4 01/12]-[PATCH v4 06/12] simplify your further changes
> without introducing regressions. While ud->lock is held when checking ud->status,
> current attach/detach code is racy about read/update of ud->status . I think we
> can close race in attach/detach code via a simple usbip_event_mutex serialization.
> 

Do you mean patches 1,2,3,3,4,5,6?

thanks,
-- Shuah