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From: Ingo Molnar <mingo@kernel.org>
To: John Stultz <john.stultz@linaro.org>
Cc: Gerlando Falauto <gerlando.falauto@keymile.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Richard Cochran <richardcochran@gmail.com>,
	Prarit Bhargava <prarit@redhat.com>,
	"Brunck, Holger" <Holger.Brunck@keymile.com>,
	"Longchamp, Valentin" <Valentin.Longchamp@keymile.com>,
	"Bigler, Stefan" <Stefan.Bigler@keymile.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: kernel deadlock
Date: Tue, 10 Sep 2013 09:29:09 +0200	[thread overview]
Message-ID: <20130910072908.GA32257@gmail.com> (raw)
In-Reply-To: <522E2FBB.4070406@linaro.org>


* John Stultz <john.stultz@linaro.org> wrote:

> Now, I'm still in the dark as to why HRTICK exposes this, but seems like 
> the following patch should resolve the issue (and quiets the lockdep 
> warnings in my testing). Let me know how it works for you!
> 
> Ingo: This makes me think we really should have some lockdep smarts 
> added to seqlock/seqcount structures. Is there something already 
> discovered thats preventing this, or has this just not yet been tried?

There's no fundamental reason to not do it, it's a very good idea!

> From 09885df9734aa678ccb61dbef356fea4faeff16c Mon Sep 17 00:00:00 2001
> From: John Stultz <john.stultz@linaro.org>
> Date: Mon, 9 Sep 2013 13:07:18 -0700
> Subject: [PATCH] timekeepeing: Fix HRTICK related deadlock from ntp lock changes

Cool fix! I think I've seen this deadlock in various incarnations but was 
never able to track it down. Do you have a guesstimate about roughly when 
it was introduced? Is it an ancient bug?

Thanks,

	Ingo

  reply	other threads:[~2013-09-10  7:29 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <521F6D06.1040107@keymile.com>
2013-08-29 20:56 ` kernel deadlock Falauto, Gerlando
2013-08-29 23:45   ` John Stultz
2013-08-30 23:04     ` Gerlando Falauto
2013-08-30 23:10       ` John Stultz
2013-08-31  0:48         ` Stephen Boyd
2013-08-31  8:11           ` Gerlando Falauto
2013-09-03 14:57         ` Gerlando Falauto
2013-09-03 17:26           ` John Stultz
2013-09-04  8:11             ` Gerlando Falauto
2013-09-09 20:29               ` John Stultz
2013-09-10  7:29                 ` Ingo Molnar [this message]
2013-09-10 16:23                   ` John Stultz
2013-09-10  7:56                 ` Peter Zijlstra
2013-09-10  8:59                 ` Lin Ming
2013-09-10 16:38                   ` John Stultz
2013-09-11  0:37                     ` Lin Ming
2013-09-09 10:08             ` Peter Zijlstra
2013-09-12 14:42               ` Gerlando Falauto
2003-07-30 20:00 Kernel deadlock Paul Douglas

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