Re: [Qemu-devel] qemu-kvm-1.0.1 - unable to exit if vcpu is in infinite loop

[Jan Kiszka]

On 2012-08-19 11:42, Avi Kivity wrote:
> On 08/17/2012 06:04 PM, Jan Kiszka wrote:
>>  
>>>> Can anyone imagine that such a barrier may actually be required? If it
>>>> is currently possible that env->stop is evaluated before we called into
>>>> sigtimedwait in qemu_kvm_eat_signals, then we could actually eat the
>>>> signal without properly processing its reason (stop).
>>
>> Should not be required (TM): Both signal eating / stop checking and stop
>> setting / signal generation happens under the BQL, thus the ordering
>> must not make a difference here.
> 
> Agree.
> 
> 
>> Don't see where we could lose a signal. Maybe due to a subtle memory
>> corruption that sets thread_kicked to non-zero, preventing the kicking
>> this way.
> 
> Cannot be ruled out, yet too much of a coincidence.
> 
> Could be a kernel bug (either in kvm or elsewhere), we've had several
> before in this area.
> 
> Is this reproducible?

Not for me. Peter only hit it very rarely, Peter obviously more easily.

Jan

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