On 06/11/2017 11:06, Wanpeng Li wrote: > 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. Is kvm_get_time_scale getting into an infinite loop then? That would be the actual bug. Paolo
