Re: [PATCH] KVM: X86: Fix softlockup when get the current kvmclock timestamp

From: Wanpeng Li
Date: Mon Nov 06 2017 - 05:06:53 EST


2017-11-06 17:29 GMT+08:00 Paolo Bonzini <pbonzini@xxxxxxxxxx>:
> On 06/11/2017 01:55, Wanpeng Li wrote:
>> This can be reproduced when running kvm-unit-tests/hyperv_stimer.flat and
>> cpu-hotplug stress simultaneously. kvm_get_time_scale() takes too long which
>> results in softlockup.
>
> Apart from the pr_debug, kvm_get_time_scale should take less than a
> microsecond. The patch is fine, but can you confirm that pr_debug is
> the culprit?

I can still encounter softlockup after removing the pr_debug.

Regards,
Wanpeng Li