From: Peter Zijlstra <peterz@infradead.org>
To: "Liu, Chuansheng" <chuansheng.liu@intel.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Yanmin Zhang <yanmin_zhang@linux.intel.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
Subject: RE: [PATCH] Fix the race between smp_call_function and CPU booting
Date: Fri, 23 Mar 2012 13:02:00 +0100 [thread overview]
Message-ID: <1332504120.16159.17.camel@twins> (raw)
In-Reply-To: <27240C0AC20F114CBF8149A2696CBE4A05D65B@SHSMSX101.ccr.corp.intel.com>
On Fri, 2012-03-23 at 11:32 +0000, Liu, Chuansheng wrote:
> In fact, I started two scripts running:
> 1/ One script:
> echo 0 > /sys/devices/system/cpuX/online
> echo 1 > /sys/devices/system/cpuX/online
> Rerunning the above commands in loop
>
> 2/Another script:
> echo 1 > /debug/smp_call_test
> usleep 50000
> Rerunning the above command in loop
>
> This race issue can be easy to be reproduced in several minutes;
> For simplify your test as mine(just two CPUs), you can set other non-booting CPUs as offline
> at first and just leave one non-booting CPU.
So this is exactly what I did and it ran for 30+ minutes without fail. I
found I forgot to log the serial output so I just re-ran this to make
sure. 10+ minutes and not a single WARN in the console output.
If I pop my change to select_fallback_rq() I can indeed trigger this:
------------[ cut here ]------------
WARNING: at /usr/src/linux-2.6/arch/x86/kernel/smp.c:120
native_smp_send_reschedule+0x5b/0x60()
Hardware name: X8DTN
Modules linked in: [last unloaded: scsi_wait_scan]
Pid: 1542, comm: abrtd Not tainted 3.3.0-01725-gd6eb054-dirty #63
Call Trace:
<IRQ> [<ffffffff810775df>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8107763a>] warn_slowpath_null+0x1a/0x20
[<ffffffff8105f79b>] native_smp_send_reschedule+0x5b/0x60
[<ffffffff810aa67a>] try_to_wake_up+0x1fa/0x2c0
[<ffffffff810acaec>] ? sched_slice.isra.38+0x5c/0x90
[<ffffffff810aa795>] wake_up_process+0x15/0x20
[<ffffffff81085c6e>] process_timeout+0xe/0x10
[<ffffffff81086cb3>] run_timer_softirq+0x143/0x460
[<ffffffff81384a94>] ? timerqueue_add+0x74/0xc0
[<ffffffff81085c60>] ? usleep_range+0x50/0x50
[<ffffffff8107e81d>] __do_softirq+0xbd/0x290
[<ffffffff810c5e64>] ? clockevents_program_event+0x74/0x100
[<ffffffff810c72d4>] ? tick_program_event+0x24/0x30
[<ffffffff8194ba4c>] call_softirq+0x1c/0x30
[<ffffffff810433d5>] do_softirq+0x55/0x90
[<ffffffff8107ed2e>] irq_exit+0x9e/0xe0
[<ffffffff8194c07e>] smp_apic_timer_interrupt+0x6e/0x99
[<ffffffff8194b107>] apic_timer_interrupt+0x67/0x70
<EOI>
---[ end trace d2b2cbf78c1ddd2e ]---
But let me re-run with the select_fallback_rq() change and let it run
for several hours while I go play outside..
next prev parent reply other threads:[~2012-03-23 12:02 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-12 9:27 [PATCH] Fix the race between smp_call_function and CPU booting Liu, Chuansheng
2012-03-12 9:32 ` Peter Zijlstra
2012-03-13 6:43 ` Liu, Chuansheng
2012-03-12 9:58 ` Peter Zijlstra
2012-03-13 6:46 ` Liu, Chuansheng
2012-03-13 15:57 ` Peter Zijlstra
2012-03-14 6:27 ` Liu, Chuansheng
2012-03-14 9:43 ` Peter Zijlstra
2012-03-15 0:11 ` Liu, Chuansheng
2012-03-15 10:46 ` Peter Zijlstra
2012-03-16 6:24 ` Liu, Chuansheng
2012-03-16 9:49 ` Peter Zijlstra
2012-03-19 0:58 ` Liu, Chuansheng
2012-03-19 10:03 ` Peter Zijlstra
2012-03-20 0:22 ` Liu, Chuansheng
2012-03-20 12:17 ` Peter Zijlstra
2012-03-20 13:14 ` Srivatsa S. Bhat
2012-03-20 13:41 ` Peter Zijlstra
2012-03-20 15:02 ` Srivatsa S. Bhat
2012-03-21 5:59 ` Liu, Chuansheng
2012-03-21 9:12 ` Peter Zijlstra
2012-03-21 12:25 ` Peter Zijlstra
2012-03-22 0:59 ` Liu, Chuansheng
2012-03-23 10:25 ` Peter Zijlstra
2012-03-23 11:32 ` Liu, Chuansheng
2012-03-23 12:02 ` Peter Zijlstra [this message]
2012-03-23 12:06 ` Liu, Chuansheng
2012-03-23 12:13 ` Peter Zijlstra
2012-03-23 12:21 ` Liu, Chuansheng
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