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Date: Tue, 10 Apr 2018 11:07:03 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Nicholas Piggin <npiggin@gmail.com>
cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alexey Kardashevskiy <aik@ozlabs.ru>, linuxppc-dev@lists.ozlabs.org,
        kvm-ppc@vger.kernel.org, Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: Occasionally losing the tick_sched_timer
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On Tue, 10 Apr 2018, Nicholas Piggin wrote:
> On Tue, 10 Apr 2018 09:42:29 +0200 (CEST)
> Thomas Gleixner <tglx@linutronix.de> wrote:
> > > Thomas do you have any ideas on what we might look for, or if we can add
> > > some BUG_ON()s to catch this at its source?  
> > 
> > Not really. Tracing might be a more efficient tool that random BUG_ONs.
> 
> Sure, we could try that. Any suggestions? timer events?

timer, hrtimer and the tick-sched stuff should be a good start. And make
sure to freeze the trace once you hit the fault case. tracing_off() is your
friend.

Thanks,

	tglx