Re: [Xen-devel] Re: PROBLEM: 3.0-rc kernels unbootable since -rc3

Paul E. McKenney
2011-07-12T14:11:27Z

On Tue, Jul 12, 2011 at 08:33:17AM +0200, Sander Eikelenboom wrote:
> Monday, July 11, 2011, 9:30:22 PM, you wrote:
>
> >>
> >> Hmmm... Does the stall repeat about every 3.5 minutes after the first stall?
>
> > Starting Configure read-only root support...
> > [ 81.335070] INFO: rcu_sched_state detected stalls on CPUs/tasks: { 0} (detected by 3, t=60002 jiffies)
> > [ 81.335091] sending NMI to all CPUs:
> > [ 261.367071] INFO: rcu_sched_state detected stalls on CPUs/tasks: { 0} (detected by 3, t=240034 jiffies)
> > [ 261.367092] sending NMI to all CPUs:
> > [ 441.399066] INFO: rcu_sched_state detected stalls on CPUs/tasks: { 0} (detected by 3, t=420066 jiffies)
> > [ 441.399089] sending NMI to all CPUs:
>
> >>
> >> One thing to try would be to disable CONFIG_RCU_FAST_NO_HZ. I wouldn't
> >> expect this to have any effect, but might be worth a try. It is really
>
> > Did not help.
> >> intended for small battery-powered systems.
> >>
>
> Just as a note, i'm also seeing some stalls from domU's running a 3.0-rc kernel from you master tree (about 2 week old).
> But it seems the first occurrences are not as quick after being booted. Unfortunately i haven't got time to investigate more this week.

Should you get some time, providing the stack traces from the CPU stall
warnings would give me something to go on. ;-)

Thanx, Paul