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Date: Wed, 10 Mar 2010 13:10:38 GMT
From: tip-bot for Peter Zijlstra <a.p.zijlstra@chello.nl>
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To: linux-tip-commits@vger.kernel.org
Subject: [tip:perf/urgent] perf, x86, Do not user perf_disable from NMI context
Message-ID: <tip-3fb2b8ddcc6a7aa62af6bd2cb939edfd4c460506@git.kernel.org>
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Commit-ID:  3fb2b8ddcc6a7aa62af6bd2cb939edfd4c460506
Gitweb:     http://git.kernel.org/tip/3fb2b8ddcc6a7aa62af6bd2cb939edfd4c460506
Author:     Peter Zijlstra <a.p.zijlstra@chello.nl>
AuthorDate: Mon, 8 Mar 2010 13:51:01 +0100
Committer:  Ingo Molnar <mingo@elte.hu>
CommitDate: Wed, 10 Mar 2010 13:22:26 +0100

perf, x86, Do not user perf_disable from NMI context

Explicitly use intel_pmu_{disable,enable}_all() in intel_pmu_handle_irq()
to avoid the NMI race conditions in perf_{disable,enable}

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: paulus@samba.org
Cc: eranian@google.com
Cc: robert.richter@amd.com
Cc: fweisbec@gmail.com
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
 arch/x86/kernel/cpu/perf_event_intel.c |   11 +++++------
 1 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 12e811a..c582449 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -745,11 +745,11 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
 
 	cpuc = &__get_cpu_var(cpu_hw_events);
 
-	perf_disable();
+	intel_pmu_disable_all();
 	intel_pmu_drain_bts_buffer();
 	status = intel_pmu_get_status();
 	if (!status) {
-		perf_enable();
+		intel_pmu_enable_all();
 		return 0;
 	}
 
@@ -759,8 +759,7 @@ again:
 		WARN_ONCE(1, "perfevents: irq loop stuck!\n");
 		perf_event_print_debug();
 		intel_pmu_reset();
-		perf_enable();
-		return 1;
+		goto done;
 	}
 
 	inc_irq_stat(apic_perf_irqs);
@@ -790,8 +789,8 @@ again:
 	if (status)
 		goto again;
 
-	perf_enable();
-
+done:
+	intel_pmu_enable_all();
 	return 1;
 }