From 1424a09a9e1839285e948d4ea9fdfca26c9a2086 Mon Sep 17 00:00:00 2001 From: Stephane Eranian Date: Thu, 3 Dec 2015 23:33:18 +0100 Subject: [PATCH] perf/x86: fix PEBS issues on Intel Atom/Core2 This patch fixes broken PEBS support on Intel Atom and Core2 due to wrong pointer arithmetic in intel_pmu_drain_pebs_core(). The get_next_pebs_record_by_bit() was called on PEBS format fmt0 which does not use the pebs_record_nhm layout. Signed-off-by: Stephane Eranian Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vince Weaver Cc: kan.liang@intel.com Fixes: 21509084f999 ("perf/x86/intel: Handle multiple records in the PEBS buffer") Link: http://lkml.kernel.org/r/1449182000-31524-3-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/perf_event_intel_ds.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c b/arch/x86/kernel/cpu/perf_event_intel_ds.c index 9c0f8d464bc0..a7463ed0b40e 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c @@ -1106,6 +1106,13 @@ get_next_pebs_record_by_bit(void *base, void *top, int bit) void *at; u64 pebs_status; + /* + * fmt0 does not have a status bitfield (does not use + * perf_record_nhm format) + */ + if (x86_pmu.intel_cap.pebs_format < 1) + return base; + if (base == NULL) return NULL; @@ -1191,7 +1198,7 @@ static void intel_pmu_drain_pebs_core(struct pt_regs *iregs) if (!event->attr.precise_ip) return; - n = (top - at) / x86_pmu.pebs_record_size; + n = top - at; if (n <= 0) return; -- 2.20.1