Re: frequent lockups in 3.18rc4

From: Dave Jones
Date: Sat Dec 27 2014 - 11:50:07 EST

On Fri, Dec 26, 2014 at 07:14:55PM -0800, Linus Torvalds wrote:
> On Fri, Dec 26, 2014 at 4:36 PM, Dave Jones <davej@xxxxxxxxxxxxxxxxx> wrote:
> > >
> > > Oh - and have you actually seen the "TSC unstable (delta = xyz)" +
> > > "switched to hpet" messages there yet?
> >
> > not yet. 3 hrs in.
> Ok, so then the
> INFO: rcu_preempt detected stalls on CPUs/tasks:
> has nothing to do with HPET, since you'd still be running with the TSC enabled.

right. 16hrs later, that's the only thing that's spewed.

> My googling around did find a number of "machine locks up a few hours
> after switching to hpet" reports, so it is possible that the whole rcu
> stall and nmi watchdog thing is independent and unrelated to the
> actual locking up.

possible. I'm heading home in a few hours to start the wipe of that
box. This is going to be 'the one that got away', but at least we've
managed to find a number of other things that needed fixing along the way.

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