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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>,
	Arnaldo Carvalho de Melo <acme@infradead.org>,
	Paul Mackerras <paulus@samba.org>,
	Pekka Enberg <penberg@kernel.org>,
	Vegard Nossum <vegardno@ifi.uio.no>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [BUG] perf and kmemcheck : fatal combination
Date: Tue, 26 Apr 2011 09:38:45 +0200	[thread overview]
Message-ID: <1303803525.20212.20.camel@twins> (raw)
In-Reply-To: <1303747731.2747.182.camel@edumazet-laptop>

On Mon, 2011-04-25 at 18:08 +0200, Eric Dumazet wrote:
> Hi guys
> 
> Just got a panic on a kmemcheck kernel, latest linux-2.6 tree.
> 
> I forgot I had kmemcheck enabled, and started "perf top" just because my
> machine was damn slow... Oh well...
> 
> Crash in do_nmi -> nmi_enter() -> BUG_ON(in_nmi());

Hmm,. I bet because kmemcheck triggers faults from nmi context because
it messes about with the page protection bits a lot to track things.

Can't really think of anything except not making perf available on
kmemcheck kernels.

---
 init/Kconfig |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/init/Kconfig b/init/Kconfig
index 32745bf..94735b4 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1125,6 +1125,7 @@ config PERF_EVENTS
 	bool "Kernel performance events and counters"
 	default y if (PROFILING || PERF_COUNTERS)
 	depends on HAVE_PERF_EVENTS
+	depends on !KMEMCHECK
 	select ANON_INODES
 	select IRQ_WORK
 	help


  reply	other threads:[~2011-04-26  7:39 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-04-25 16:08 [BUG] perf and kmemcheck : fatal combination Eric Dumazet
2011-04-26  7:38 ` Peter Zijlstra [this message]
2011-04-26  7:43   ` Pekka Enberg
2011-04-26  8:04   ` Ingo Molnar
2011-04-26  8:57     ` Eric Dumazet
2011-04-26  9:53       ` Eric Dumazet
2011-04-26 10:08         ` Pekka Enberg
2011-04-26 10:27           ` Eric Dumazet
2011-04-26 12:27             ` Eric Dumazet
2011-04-26 12:33               ` Peter Zijlstra
2011-04-26 12:56                 ` Eric Dumazet
2011-04-26 13:09                   ` Eric Dumazet
2011-04-26 19:13                 ` Pekka Enberg
2011-04-26 13:53         ` Mathieu Desnoyers

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