From: Clark Williams <williams@redhat.com>
To: paulmck@linux.vnet.ibm.com
Cc: Thomas Gleixner <tglx@linutronix.de>,
RT <linux-rt-users@vger.kernel.org>
Subject: Re: [RT] RCU splat on 2.6.33.4-rt20
Date: Thu, 20 May 2010 08:59:27 -0500 [thread overview]
Message-ID: <20100520085927.480047d4@torg> (raw)
In-Reply-To: <20100520032246.GB2708@linux.vnet.ibm.com>
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On Wed, 19 May 2010 20:22:46 -0700
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com> wrote:
> On Wed, May 19, 2010 at 09:19:11PM -0500, Clark Williams wrote:
> > Thomas/Paul,
> >
> > Resumed my laptop (T60, 64-bit kernel) and after about five
> > minutes of doing nothing but surfing with firefox, got the following
> > RCU stall notification from a 2.6.33.4-rt20 kernel:
> >
> > INFO: RCU detected CPU 1 stall (t=0 jiffies)
>
> Hmmm... "t=0 jiffies". I wonder if the hibernation/resumption confused
> the stall-warning code. My first thought was that an RCU grace period
> had spanned the hibernation, but that would not be consistent with it
> waiting five minutes after resumption to splat.
>
> I will look into this.
>
Don't take that "five minutes" as anything approaching some degree of
accuracy. It could have been quicker; I was distracted and not even
touching the keyboard when a loud beep sounded and I had to poke around
a bit to realize that an NMI backtrace had triggered.
Depending on your timeout values, I think that it's quite reasonable to
suspect that an RCU spanned the suspend/resume.
Clark
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prev parent reply other threads:[~2010-05-20 13:59 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-20 2:19 [RT] RCU splat on 2.6.33.4-rt20 Clark Williams
2010-05-20 3:22 ` Paul E. McKenney
2010-05-20 13:59 ` Clark Williams [this message]
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