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From: Sasha Levin <levinsasha928@gmail.com>
To: paulmck@linux.vnet.ibm.com
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6
Date: Tue, 24 Jul 2012 22:55:07 +0200	[thread overview]
Message-ID: <500F0BAB.7060001@gmail.com> (raw)
In-Reply-To: <20120724174017.GE2390@linux.vnet.ibm.com>

On 07/24/2012 07:40 PM, Paul E. McKenney wrote:
> The interrupt flag is zero, so interrupts are disabled.  So my question
> to you is "Why did do_pageattr_test() or one of the functions it called
> disable interrupts for more than one hundred thousand jiffies?"
> 
> I can't see where it is disabling interrupts, but the EFLAGS register
> above does indicate that they are disabled.  Or is this something useless
> that is just telling us that receiving the NMI disabled interrupts?

Doesn't the stack of CPU1 show that it's currently handling an interrupt:

[  215.026612] Call Trace:
[  215.026612]  <IRQ>
[  215.026612]  [<ffffffff81095d07>] native_apic_msr_eoi_write+0x27/0x30
[  215.026612]  [<ffffffff810901c4>] smp_apic_timer_interrupt+0x34/0xa0
[  215.026612]  [<ffffffff8369c4af>] apic_timer_interrupt+0x6f/0x80
[  215.026612]  <EOI>

Or am I reading that wrong?

In that case, it had nothing to do with pageattr which just happened to be on the stack at that time.

  reply	other threads:[~2012-07-24 20:54 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-24 17:10 rcu: INFO: rcu_preempt detected stalls on CPUs/tasks on v3.6 Sasha Levin
2012-07-24 17:40 ` Paul E. McKenney
2012-07-24 20:55   ` Sasha Levin [this message]
2012-07-25  8:36 ` Michael Wang
2012-07-25 21:16   ` Sasha Levin
2012-07-26  5:10     ` Michael Wang
2012-07-25  9:06 ` Michael Wang
2012-07-26 11:42 ` Avi Kivity
2012-07-27 11:27   ` Sasha Levin
2012-07-29 12:48     ` Avi Kivity
2012-07-29 21:05       ` Sasha Levin
2012-07-30  5:36         ` Avi Kivity
2012-07-30  9:13           ` Sasha Levin
2012-07-30  9:33             ` Avi Kivity
2012-07-30 12:43               ` Sasha Levin
2012-07-30 13:17                 ` Avi Kivity
2012-08-05 16:55                   ` Sasha Levin
2012-08-06 17:21                     ` John Stultz
2012-08-06 18:12                       ` John Stultz
2012-08-06 18:20                       ` John Stultz
2012-08-06 18:28                         ` Sasha Levin
2012-08-06 20:31                           ` John Stultz
2012-08-06 20:35                             ` Sasha Levin
2012-08-07  5:05                               ` Michael Wang
2012-08-07  5:40                           ` John Stultz
2012-08-07 10:24                             ` Sasha Levin
2012-08-08  2:20                               ` Michael Wang
2012-08-06 19:24                       ` Sasha Levin

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