Messages in this thread | | | Date | Thu, 9 Oct 2008 06:56:46 +0200 | From | Andi Kleen <> | Subject | Re: RCU hang on cpu re-hotplug with 2.6.27rc8 |
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[fix up Thomas' address to not bounce]
On Wed, Oct 08, 2008 at 06:33:21PM -0700, Paul E. McKenney wrote: > The attached patch (similar to one in -tip, but set up for mainline and > tweaked to make stall-checking on by default) should get you a stack > trace of any CPUs holding up RCU grace periods for more than about > three seconds. > > On the off-chance that this helps.
It actually does. The stall detector makes the online echo return after three seconds, although it's not 100% clear to me why.
here's the backtrace
RCU detected CPU 14 stall (t=4295149800/5928 jiffies) Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #5
Call Trace: <IRQ> [<ffffffff8025d188>] __rcu_pending+0x6e/0x1d9 [<ffffffff8025d329>] rcu_pending+0x36/0x6e [<ffffffff8023b480>] update_process_times+0x37/0x5b [<ffffffff8024be72>] tick_periodic+0x68/0x74 [<ffffffff8024be9f>] tick_handle_periodic+0x21/0x66 [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 [<ffffffff8020bfe6>] apic_timer_interrupt+0x66/0x70 <EOI> [<ffffffff803adb39>] ? acpi_safe_halt+0x2b/0x3e [<ffffffff803adbfa>] ? acpi_idle_enter_c1+0xae/0x102 [<ffffffff804ffdd6>] ? cpuidle_idle_call+0x70/0xa2 [<ffffffff8020a097>] ? cpu_idle+0x7e/0x9c [<ffffffff805bef4a>] ? start_secondary+0x157/0x15c
Timer issue?
-Andi
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