Messages in this thread | | | Date | Fri, 20 May 2011 02:14:23 +0200 | From | Frederic Weisbecker <> | Subject | Re: [GIT PULL rcu/next] rcu commits for 2.6.40 |
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On Thu, May 19, 2011 at 02:45:52PM -0700, Yinghai Lu wrote: > On 05/19/2011 02:15 PM, Frederic Weisbecker wrote: > > On Thu, May 19, 2011 at 12:51:26PM -0700, Yinghai Lu wrote: > >> [ 85.194797] <idle>-0 0d... 85152953us : rcu_irq_enter: 1 49 > >> [ 85.194808] <idle>-0 0dN.. 85153081us : <stack trace> > >> [ 85.194809] => rcu_irq_exit > >> [ 85.194810] => irq_exit > >> [ 85.194811] => smp_apic_timer_interrupt > >> [ 85.194812] => apic_timer_interrupt > >> [ 85.194813] => cpu_idle > >> [ 85.194813] => rest_init > >> [ 85.194814] => start_kernel > >> [ 85.194815] => x86_64_start_reservations > > > > So it's the dynticks_nesting going crazy. As if we had rcu_irq_enter() > > without rcu_irq_exit(). > > > > I see you have CONFIG_DEBUG_LOCKING_API_SELFTESTS=y > > and the locking api selftest is doing a strange thing: if we look > > at HARDIRQ_ENTER(), it calls irq_enter(), but HARDIRQ_EXIT() only > > calls __irq_exit(). Which means it lacks the rcu_irq_exit(). > > > > So, if I understood correctly the thing there, some selftests simulating > > the hardirq context are unbalancing the rcu state. > > > > Does that help if you unset CONFIG_DEBUG_LOCKING_API_SELFTESTS ? > > > yes, after unset that, no warning and delay...
Thanks a lot for all your testing! I've just proposed a fix, let's see how that goes.
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