Re: [PATCH] time/tick-broadcast: Fix tick_broadcast_offline() lockdep complaint

From: Paul E. McKenney
Date: Fri Jun 21 2019 - 08:16:36 EST


On Fri, Jun 21, 2019 at 12:55:03PM +0200, Peter Zijlstra wrote:
> On Thu, Jun 20, 2019 at 03:13:36PM -0700, Paul E. McKenney wrote:
> > So how about the following patch, which passes very light rcutorture
> > testing but should otherwise be regarded as being under suspicion?
>
> Looks good to me,
>
> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>

Thank you! But...

> Or, if you want me to apply it, I can do that too ;-)

Last night's rcutorture run was not amused. Looking into it...

A pair of full hangs at boot (TASKS03 and TREE04), no console output
whatsoever. Not sure how these changes could cause that, but suspicion
falls on sched_tick_offload_init(). Though even that is a bit strange
because if so, why didn't TREE01 and TREE07 also hang? Again, looking
into it.

Thanx, Paul