Panic with vboxnet drivers

[Fredrik Lindberg]

Sean C. Farley wrote:
>>> 2. The next three logs are LOR's (sleepable after non-sleepable)
>>>    concerning VirtualBox's "IPRT Fast Mutex Semaphore" which is an
>>>    sx.  I am not sure I am reading the backtrace correctly.  It looks
>>>    like the call to RTSemFastMutexRequest(), which calls sx_xlock(),
>>>    is the effect.  I just do not know where the cause, i.e.,
>>>    RTSemFastMutexRequest(), is being called.
>>
>> Yeah, this was a real one. The call to RTSemFastMutexRequest is inside 
>> the virtual ethernet switch.  I've attached a patch that defers 
>> processing to avoid the sleepable after non-sleepable case.  Hopefully 
>> this fixes the panic you're seeing as well.
> 
> Thank you!  :)  This does fix the panic.
> 

Great, I'll submit it upstreams as soon as possible.

Fredrik