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From: Ingo Molnar <mingo@kernel.org>
To: Dave Hansen <dave@sr71.net>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] x86: perf: fix incorrect use of do_div() in nmi warning
Date: Fri, 12 Jul 2013 14:08:43 +0200	[thread overview]
Message-ID: <20130712120843.GA21708@gmail.com> (raw)
In-Reply-To: <20130708214404.B0B6EA66@viggo.jf.intel.com>


* Dave Hansen <dave@sr71.net> wrote:

> 
> From: Dave Hansen <dave.hansen@linux.intel.com>
> 
> This fixes a bug present in 3.10 and introduced here:
> 
> commit 2ab00456ea8a0d79acb1390659b98416111880b2
> Author: Dave Hansen <dave.hansen@linux.intel.com>
> Date:   Fri Jun 21 08:51:35 2013 -0700
> 
>     x86: Warn when NMI handlers take large amounts of time
> 
> I completely botched understanding the calling conventions of
> do_div().  I assumed that do_div() returned the result instead
> of realizing that it modifies its argument and returns a
> remainder.  The side-effect from this would be bogus numbers
> for the "msecs" value in the warning messages:
> 
> 	INFO: NMI handler (perf_event_nmi_handler) took too long to run: 0.114 msecs
> 
> Note, there was a second fix posted by Stephane Eranian for
> a separate patch which I also botched:
> 
> 	http://lkml.kernel.org/r/20130704223010.GA30625@quad
> 
> Both of these fixes need to get pulled in to Linus's tree and
> the 3.10 stable tree.

This is a brand new v3.11 commit.

It should not be included in any -stable tree, is it?

Thanks,

	Ingo

  reply	other threads:[~2013-07-12 12:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-07-08 21:44 [PATCH] x86: perf: fix incorrect use of do_div() in nmi warning Dave Hansen
2013-07-12 12:08 ` Ingo Molnar [this message]
2013-07-12 16:28   ` Dave Hansen
2013-07-12 13:30 ` [tip:perf/urgent] perf/x86: Fix incorrect use of do_div() in NMI warning tip-bot for Dave Hansen

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