Re: rcu_preempt self-detected stall on CPU from 4.5-rc3, since 3.17

From: Paul E. McKenney
Date: Sun Mar 27 2016 - 17:07:39 EST


On Sun, Mar 27, 2016 at 10:53:18PM +0200, Peter Zijlstra wrote:
> On Sun, Mar 27, 2016 at 08:40:18AM -0700, Paul E. McKenney wrote:
> > Oh, and the patch I am running with is below. I am running x86, and so
> > some other architectures would of course need the corresponding patch
> > on that architecture.
>
> > -#define TIF_POLLING_NRFLAG 21 /* idle is polling for TIF_NEED_RESCHED */
>
> Also note that ARM (v7) which Ross is running doesn't have this to begin
> with.

He might well be seeing some other bug, then. Reinette might be instead
seeing time-synchronization issues, perhaps that is also Ross's problem.

Or maybe there is more than one bug. ;-)

Thanx, Paul