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From: Ingo Molnar <mingo@elte.hu>
To: Don Zickus <dzickus@redhat.com>
Cc: fweisbec@gmail.com, Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	akpm@linux-foundation.org, sergey.senozhatsky@gmail.com
Subject: Re: [PATCH v3] watchdog:  touch_nmi_watchdog should only touch local cpu not every one
Date: Wed, 10 Nov 2010 08:49:41 +0100	[thread overview]
Message-ID: <20101110074941.GD29493@elte.hu> (raw)
In-Reply-To: <1289240913-16677-1-git-send-email-dzickus@redhat.com>


* Don Zickus <dzickus@redhat.com> wrote:

> I ran into a scenario where while one cpu was stuck and should have panic'd 
> because of the NMI watchdog, it didn't.  The reason was another cpu was spewing 
> stack dumps on to the console.  Upon investigation, I noticed that when writing to 
> the console and also when dumping the stack, the watchdog is touched.
> 
> This causes all the cpus to reset their NMI watchdog flags and the 'stuck' cpu 
> just spins forever.

Hm, the flip side is that if a CPU is stuck spewing backtraces, we will now make all 
the other CPUs a lot more noisy - which might only 'lock up' because this CPU is 
stuck spewing oopses, right?

Andrew, what would be your preference?

Thanks,

	Ingo

  reply	other threads:[~2010-11-10  7:50 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-08 18:28 [PATCH v3] watchdog: touch_nmi_watchdog should only touch local cpu not every one Don Zickus
2010-11-10  7:49 ` Ingo Molnar [this message]
2010-11-10 15:08   ` Andrew Morton
2010-11-10 16:05   ` Don Zickus
2010-11-10 18:07     ` Ingo Molnar
2010-11-10 19:03       ` Don Zickus
2010-11-10 19:14         ` Ingo Molnar
2010-11-15 18:23           ` Don Zickus

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