From: Peter Zijlstra Date: Sat, 6 Mar 2010 12:48:54 +0000 (+0100) Subject: perf, x86: Fix LBR enable/disable vs cpuc->enabled X-Git-Tag: v2.6.35-rc1~3^2~270 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=2df202bf7520eaffcbfb07e45dfa3cfb0aeee2c0;p=linux-2.6-block.git perf, x86: Fix LBR enable/disable vs cpuc->enabled We should never call ->enable with the pmu enabled, and we _can_ have ->disable called with the pmu enabled. 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 --- diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c index dcec765f8188..0145f99f7a35 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c @@ -69,7 +69,7 @@ static void intel_pmu_lbr_enable(struct perf_event *event) if (!x86_pmu.lbr_nr) return; - WARN_ON(cpuc->enabled); + WARN_ON_ONCE(cpuc->enabled); /* * Reset the LBR stack if this is the first LBR user or @@ -93,9 +93,10 @@ static void intel_pmu_lbr_disable(struct perf_event *event) return; cpuc->lbr_users--; - BUG_ON(cpuc->lbr_users < 0); - WARN_ON(cpuc->enabled); + + if (cpuc->enabled && !cpuc->lbr_users) + __intel_pmu_lbr_disable(); } static void intel_pmu_lbr_enable_all(void)