Messages in this thread | | | Date | Mon, 06 Aug 2012 20:28:54 +0200 | From | Sasha Levin <> | Subject | Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6 |
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On 08/06/2012 08:20 PM, John Stultz wrote: > On 08/06/2012 10:21 AM, John Stultz wrote: >> On 08/05/2012 09:55 AM, Sasha Levin wrote: >>> On 07/30/2012 03:17 PM, Avi Kivity wrote: >>>> Possible causes: >>>> - the APIC calibration in the guest failed, so it is programming too >>>> low values into the timer >>>> - it actually needs 1 us wakeups and then can't keep up (esp. as kvm >>>> interrupt injection is slowing it down) >>>> >>>> You can try to find out by changing >>>> arch/x86/kvm/lapic.c:start_lapic_timer() to impose a minimum wakeup of >>>> (say) 20 microseconds which will let the guest live long enough for you >>>> to ftrace it and see what kind of timers it is programming. >>> I've kept trying to narrow it down, and found out It's triggerable using adjtimex(). > Sorry, one more question: Could you provide details on how is it trigger-able using adjtimex?
It triggers after a while of fuzzing using trinity of just adjtimex ('./trinity --quiet -l off -cadjtimex').
Trinity is available here: http://git.codemonkey.org.uk/?p=trinity.git .
Let me know if I can help further with reproducing this, I can probably copy over my testing environment to some other host if you'd like.
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