linux-kernel - Re: RCU hang on cpu re-hotplug with 2.6.27rc8

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Thu, 9 Oct 2008 10:22:30 +0200
From:	Andi Kleen <andi@...stfloor.org>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	Andi Kleen <andi@...stfloor.org>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>, mingo@...e.hu,
	linux-kernel@...r.kernel.org, rjw@...k.pl, dipankar@...ibm.com
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@...ux.intel.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/