From 19925ce778f9fc371b9607625de3bff04c60121e Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Sat, 6 Mar 2010 13:20:40 +0100 Subject: [PATCH] perf, x86: Fix double disable calls hw_perf_enable() would disable events that were not yet enabled. This causes problems with code that assumes that ->enable/->disable calls are balanced (like the LBR code does). What happens is that we disable newly added counters that match their previous assignment, even though they are not yet programmed on the hardware. Avoid this by only doing the first pass over the existing events. Signed-off-by: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: paulus@samba.org Cc: eranian@google.com Cc: robert.richter@amd.com Cc: fweisbec@gmail.com LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c index 071c840..045cc0b 100644 --- a/arch/x86/kernel/cpu/perf_event.c +++ b/arch/x86/kernel/cpu/perf_event.c @@ -802,6 +802,7 @@ void hw_perf_enable(void) return; if (cpuc->n_added) { + int n_running = cpuc->n_events - cpuc->n_added; /* * apply assignment obtained either from * hw_perf_group_sched_in() or x86_pmu_enable() @@ -809,7 +810,7 @@ void hw_perf_enable(void) * step1: save events moving to new counters * step2: reprogram moved events into new counters */ - for (i = 0; i < cpuc->n_events; i++) { + for (i = 0; i < n_running; i++) { event = cpuc->event_list[i]; hwc = &event->hw; -- 2.7.4