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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>,
	Corey Ashford <cjashfor@linux.vnet.ibm.com>,
	linux-kernel@vger.kernel.org,
	Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: [PATCH 2/4] perf_counter: fix nmi-watchdog interaction
Date: Fri, 01 May 2009 12:23:17 +0200	[thread overview]
Message-ID: <20090501102533.109867793@chello.nl> (raw)
In-Reply-To: 20090501102315.367605848@chello.nl

[-- Attachment #1: perf_counter-fix-nmi.patch --]
[-- Type: text/plain, Size: 670 bytes --]

When we don't have any perf-counters active, don't act like we know
what the NMI is for.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
---
 arch/x86/kernel/cpu/perf_counter.c |    3 +++
 1 file changed, 3 insertions(+)

Index: linux-2.6/arch/x86/kernel/cpu/perf_counter.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_counter.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_counter.c
@@ -891,6 +891,9 @@ perf_counter_nmi_handler(struct notifier
 	struct pt_regs *regs;
 	int ret;
 
+	if (!atomic_read(&num_counters))
+		return NOTIFY_DONE;
+
 	switch (cmd) {
 	case DIE_NMI:
 	case DIE_NMI_IPI:

-- 


  parent reply	other threads:[~2009-05-01 10:26 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-05-01 10:23 [PATCH 0/4] perf_counter bits Peter Zijlstra
2009-05-01 10:23 ` [PATCH 1/4] perf_counter: fix race in perf_output_* Peter Zijlstra
2009-05-01 13:27   ` [tip:perfcounters/core] " tip-bot for Peter Zijlstra
2009-05-01 10:23 ` Peter Zijlstra [this message]
2009-05-01 13:27   ` [tip:perfcounters/core] perf_counter: fix nmi-watchdog interaction tip-bot for Peter Zijlstra
2009-05-01 10:23 ` [PATCH 3/4] perf_counter: tool: handle 0-length data files Peter Zijlstra
2009-05-01 13:27   ` [tip:perfcounters/core] " tip-bot for Peter Zijlstra
2009-05-01 10:23 ` [PATCH 4/4] perf_counter: documetation update Peter Zijlstra
2009-05-01 13:28   ` [tip:perfcounters/core] perf_counter: documentation update tip-bot for Peter Zijlstra

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