perf, nmi: Fix unknown NMI warning
authorMarkus Metzger <markus.t.metzger@intel.com>
Sat, 15 Feb 2014 00:44:08 +0000 (16:44 -0800)
committerThomas Gleixner <tglx@linutronix.de>
Fri, 21 Feb 2014 21:09:01 +0000 (22:09 +0100)
When using BTS on Core i7-4*, I get the below kernel warning.

$ perf record -c 1 -e branches:u ls
Message from syslogd@labpc1501 at Nov 11 15:49:25 ...
 kernel:[  438.317893] Uhhuh. NMI received for unknown reason 31 on CPU 2.

Message from syslogd@labpc1501 at Nov 11 15:49:25 ...
 kernel:[  438.317920] Do you have a strange power saving mode enabled?

Message from syslogd@labpc1501 at Nov 11 15:49:25 ...
 kernel:[  438.317945] Dazed and confused, but trying to continue

Make intel_pmu_handle_irq() take the full exit path when returning early.

Cc: eranian@google.com
Cc: peterz@infradead.org
Cc: mingo@kernel.org
Signed-off-by: Markus Metzger <markus.t.metzger@intel.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1392425048-5309-1-git-send-email-andi@firstfloor.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
arch/x86/kernel/cpu/perf_event_intel.c

index 0fa4f24..698ae77 100644 (file)
@@ -1361,10 +1361,8 @@ static int intel_pmu_handle_irq(struct pt_regs *regs)
        intel_pmu_disable_all();
        handled = intel_pmu_drain_bts_buffer();
        status = intel_pmu_get_status();
-       if (!status) {
-               intel_pmu_enable_all(0);
-               return handled;
-       }
+       if (!status)
+               goto done;
 
        loops = 0;
 again: