Messages in this thread | | | Date | Thu, 9 Oct 2008 10:22:30 +0200 | From | Andi Kleen <> | Subject | Re: RCU hang on cpu re-hotplug with 2.6.27rc8 |
| |
On Thu, Oct 09, 2008 at 09:24:51AM +0200, Thomas Gleixner wrote: > On Thu, 9 Oct 2008, Andi Kleen wrote: > > 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? > > Hmm, this is periodic mode so rather unlikely, but who knows. Does > this happen with nohz and/or highres as well ?
With nohz/highres enabled it takes much longer to trigger. Normally it happened near always on the first try, now I had to let a loop run for several minutes to trigger it.
But the strange thing is that the stall detector doesn't detect the hotplugged CPUs stalling now, but other unrelated ones. I only hotplug 14/15, but it reports 3 and 4. In periodic mode the correct CPUs were reported.
-Andi
Here are the backtraces
Switched to high resolution mode on CPU 14 CPU 15 is now offline RCU detected CPU 3 stall (t=4294999688/3809 jiffies) Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #6
Call Trace: <IRQ> [<ffffffff8025f474>] __rcu_pending+0x6e/0x1d9 [<ffffffff8025f615>] rcu_pending+0x36/0x6e [<ffffffff8023bc5d>] update_process_times+0x37/0x5b [<ffffffff8024de88>] tick_sched_timer+0x81/0xb5 [<ffffffff80247538>] __run_hrtimer+0x56/0x96 [<ffffffff80248002>] hrtimer_interrupt+0xe6/0x14d [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 [<ffffffff8020bff6>] apic_timer_interrupt+0x66/0x70 <EOI> [<ffffffff803b0254>] ? acpi_idle_enter_bm+0x2a2/0x312 [<ffffffff803b024a>] ? acpi_idle_enter_bm+0x298/0x312 [<ffffffff805020c2>] ? cpuidle_idle_call+0x70/0xa2 [<ffffffff8020a0a1>] ? cpu_idle+0x88/0xae [<ffffffff805c137a>] ? start_secondary+0x157/0x15c
RCU detected CPU 3 stall (t=4295007688/1250 jiffies) Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #6
Call Trace: <IRQ> [<ffffffff8025f474>] __rcu_pending+0x6e/0x1d9 [<ffffffff8025f615>] rcu_pending+0x36/0x6e [<ffffffff8023bc5d>] update_process_times+0x37/0x5b [<ffffffff8024de88>] tick_sched_timer+0x81/0xb5 [<ffffffff80247538>] __run_hrtimer+0x56/0x96 [<ffffffff80248002>] hrtimer_interrupt+0xe6/0x14d [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 [<ffffffff8020bff6>] apic_timer_interrupt+0x66/0x70 <EOI> [<ffffffff803b0254>] ? acpi_idle_enter_bm+0x2a2/0x312 [<ffffffff803b024a>] ? acpi_idle_enter_bm+0x298/0x312 [<ffffffff805020c2>] ? cpuidle_idle_call+0x70/0xa2 [<ffffffff8020a0a1>] ? cpu_idle+0x88/0xae [<ffffffff805c137a>] ? start_secondary+0x157/0x15c
RCU detected CPU 3 stall (t=4295012121/2548 jiffies) Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #6
Call Trace: <IRQ> [<ffffffff8025f474>] __rcu_pending+0x6e/0x1d9 [<ffffffff8025f640>] rcu_pending+0x61/0x6e [<ffffffff8023bc5d>] update_process_times+0x37/0x5b [<ffffffff8024de88>] tick_sched_timer+0x81/0xb5 [<ffffffff80247538>] __run_hrtimer+0x56/0x96 [<ffffffff80248002>] hrtimer_interrupt+0xe6/0x14d [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 [<ffffffff8020bff6>] apic_timer_interrupt+0x66/0x70 <EOI> [<ffffffff803b0254>] ? acpi_idle_enter_bm+0x2a2/0x312 [<ffffffff803b024a>] ? acpi_idle_enter_bm+0x298/0x312 [<ffffffff805020c2>] ? cpuidle_idle_call+0x70/0xa2 [<ffffffff8020a0a1>] ? cpu_idle+0x88/0xae [<ffffffff805c137a>] ? start_secondary+0x157/0x15c
RCU detected CPU 2 stall (t=4295014976/874 jiffies) Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #6
Call Trace: <IRQ> <3>RCU detected CPU 3 stall (t=4295014976/874 jiffies) [<ffffffff8025f474>] __rcu_pending+0x6e/0x1d9 [<ffffffff8025f615>] rcu_pending+0x36/0x6e [<ffffffff8023bc5d>] update_process_times+0x37/0x5b [<ffffffff8024de88>] tick_sched_timer+0x81/0xb5 [<ffffffff80247538>] __run_hrtimer+0x56/0x96 [<ffffffff80248002>] hrtimer_interrupt+0xe6/0x14d [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #6
Call Trace: <IRQ> [<ffffffff8020bff6>] apic_timer_interrupt+0x66/0x70 <EOI> [<ffffffff8024e1b0>] ? tick_nohz_restart_sched_tick+0x15e/0x165 [<ffffffff8025f474>] __rcu_pending+0x6e/0x1d9 [<ffffffff8025f615>] rcu_pending+0x36/0x6e [<ffffffff8023bc5d>] update_process_times+0x37/0x5b [<ffffffff8024de88>] tick_sched_timer+0x81/0xb5 [<ffffffff80247538>] __run_hrtimer+0x56/0x96 [<ffffffff80248002>] hrtimer_interrupt+0xe6/0x14d [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 [<ffffffff8020a0bd>] ? cpu_idle+0xa4/0xae [<ffffffff805c137a>] ? start_secondary+0x157/0x15c [<ffffffff8020bff6>] apic_timer_interrupt+0x66/0x70
<EOI> [<ffffffff803b0254>] ? acpi_idle_enter_bm+0x2a2/0x312 [<ffffffff803b024a>] ? acpi_idle_enter_bm+0x298/0x312 [<ffffffff805020c2>] ? cpuidle_idle_call+0x70/0xa2 [<ffffffff8020a0a1>] ? cpu_idle+0x88/0xae [<ffffffff805c137a>] ? start_secondary+0x157/0x15c
RCU detected CPU 4 stall (t=4295019871/4894 jiffies) Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #6
Call Trace: <IRQ> [<ffffffff8025f474>] __rcu_pending+0x6e/0x1d9 [<ffffffff8025f615>] rcu_pending+0x36/0x6e [<ffffffff8023bc5d>] update_process_times+0x37/0x5b [<ffffffff8024de88>] tick_sched_timer+0x81/0xb5 [<ffffffff80247538>] __run_hrtimer+0x56/0x96 RCU detected CPU 6 stall (t=4295019871/4894 jiffies) Pid: 0, comm: swapper Not tainted 2.6.27-rc9 #6
Call Trace: <IRQ> [<ffffffff8025f474>] __rcu_pending+0x6e/0x1d9 [<ffffffff80248002>] hrtimer_interrupt+0xe6/0x14d [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 [<ffffffff8020bff6>] apic_timer_interrupt+0x66/0x70 <EOI> [<ffffffff803b0254>] ? acpi_idle_enter_bm+0x2a2/0x312 [<ffffffff8025f615>] rcu_pending+0x36/0x6e [<ffffffff8023bc5d>] update_process_times+0x37/0x5b [<ffffffff8024de88>] tick_sched_timer+0x81/0xb5 [<ffffffff80247538>] __run_hrtimer+0x56/0x96 [<ffffffff80248002>] hrtimer_interrupt+0xe6/0x14d [<ffffffff8021bcd2>] smp_apic_timer_interrupt+0x8a/0xa8 [<ffffffff8020bff6>] apic_timer_interrupt+0x66/0x70 <EOI> [<ffffffff8024e1b0>] ? tick_nohz_restart_sched_tick+0x15e/0x165 [<ffffffff803b024a>] ? acpi_idle_enter_bm+0x298/0x312 [<ffffffff805020c2>] ? cpuidle_idle_call+0x70/0xa2 [<ffffffff8020a0a1>] ? cpu_idle+0x88/0xae [<ffffffff805c137a>] ? start_secondary+0x157/0x15c
[<ffffffff8020a0bd>] ? cpu_idle+0xa4/0xae [<ffffffff805c137a>] ? start_secondary+0x157/0x15c
-- ak@linux.intel.com
| |