From: Markus Metzger <[email protected]> 3.12-stable review patch. If anyone has any objections, please let me know.
=============== commit a3ef2229c94ff70998724cb64b9cb4c77db9e950 upstream. 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: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Markus Metzger <[email protected]> Signed-off-by: Andi Kleen <[email protected]> Signed-off-by: Peter Zijlstra <[email protected]> Link: http://lkml.kernel.org/r/[email protected] Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Jiri Slaby <[email protected]> --- arch/x86/kernel/cpu/perf_event_intel.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c index b400d0be5b03..d2080aa4322a 100644 --- a/arch/x86/kernel/cpu/perf_event_intel.c +++ b/arch/x86/kernel/cpu/perf_event_intel.c @@ -1341,10 +1341,8 @@ 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: -- 2.8.1
