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
next prev parent 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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