Re: rcu: BUG: spinlock recursion on CPU#3, trinity-child19/5970

Paul E. McKenney
2012-07-02T15:13:16Z

On Mon, Jul 02, 2012 at 04:36:53PM +0200, Sasha Levin wrote:
> On Mon, 2012-07-02 at 07:22 -0700, Paul E. McKenney wrote:
> > > OK, so it looks like the context-switch-time call into preemptible RCU
> > > needs to be outside of the runqueue-lock critical section. One way
> > > to do this is be reverting 616c310e (Move PREEMPT_RCU preemption to
> > > switch_to() invocation). Sasha, could you please try this out?
> >
> > Hmmmm... Here is a patch for this reversion on top of -rcu with
> > conflicts resolved.
>
> It looks like how I've resolved it.

Good show!!!

> Just for clarity, the only rcu related patch I have on top of -next is
> this reversal one. I've dropped anything we tested before.
>
> Looks like its running fine for a bit now (~10 min). I'll ping if
> anything changes, but on the other tests it has usually failed at this
> point.

If testing goes well (both yours and mine), I will be submitting this
as urgent, since it is a 3.5 regression. If they don't take it, I will
queue it for 3.6.

Thanx, Paul