3 files changed, 23 insertions, 8 deletions

diff --git a/arch/x86/kernel/cpu/perf_event.h b/arch/x86/kernel/cpu/perf_event.h
index ce84edeeae27..fd00bb29425d 100644
--- a/arch/x86/kernel/cpu/perf_event.h
+++ b/arch/x86/kernel/cpu/perf_event.h
@@ -445,6 +445,7 @@ struct x86_pmu {
 	int		lbr_nr;			   /* hardware stack size */
 	u64		lbr_sel_mask;		   /* LBR_SELECT valid bits */
 	const int	*lbr_sel_map;		   /* lbr_select mappings */
+	bool		lbr_double_abort;	   /* duplicated lbr aborts */
 
 	/*
 	 * Extra registers for events
diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
index 36b5ab884c15..0fa4f242f050 100644
--- a/arch/x86/kernel/cpu/perf_event_intel.c
+++ b/arch/x86/kernel/cpu/perf_event_intel.c
@@ -2519,6 +2519,7 @@ __init int intel_pmu_init(void)
 		x86_pmu.hw_config = hsw_hw_config;
 		x86_pmu.get_event_constraints = hsw_get_event_constraints;
 		x86_pmu.cpu_events = hsw_events_attrs;
+		x86_pmu.lbr_double_abort = true;
 		pr_cont("Haswell events, ");
 		break;
 
diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index d5be06a5005e..90ee6c1d0542 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -284,6 +284,7 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
 	int lbr_format = x86_pmu.intel_cap.lbr_format;
 	u64 tos = intel_pmu_lbr_tos();
 	int i;
+	int out = 0;
 
 	for (i = 0; i < x86_pmu.lbr_nr; i++) {
 		unsigned long lbr_idx = (tos - i) & mask;
@@ -306,15 +307,27 @@ static void intel_pmu_lbr_read_64(struct cpu_hw_events *cpuc)
 		}
 		from = (u64)((((s64)from) << skip) >> skip);
 
-		cpuc->lbr_entries[i].from	= from;
-		cpuc->lbr_entries[i].to		= to;
-		cpuc->lbr_entries[i].mispred	= mis;
-		cpuc->lbr_entries[i].predicted	= pred;
-		cpuc->lbr_entries[i].in_tx	= in_tx;
-		cpuc->lbr_entries[i].abort	= abort;
-		cpuc->lbr_entries[i].reserved	= 0;
+		/*
+		 * Some CPUs report duplicated abort records,
+		 * with the second entry not having an abort bit set.
+		 * Skip them here. This loop runs backwards,
+		 * so we need to undo the previous record.
+		 * If the abort just happened outside the window
+		 * the extra entry cannot be removed.
+		 */
+		if (abort && x86_pmu.lbr_double_abort && out > 0)
+			out--;
+
+		cpuc->lbr_entries[out].from	 = from;
+		cpuc->lbr_entries[out].to	 = to;
+		cpuc->lbr_entries[out].mispred	 = mis;
+		cpuc->lbr_entries[out].predicted = pred;
+		cpuc->lbr_entries[out].in_tx	 = in_tx;
+		cpuc->lbr_entries[out].abort	 = abort;
+		cpuc->lbr_entries[out].reserved	 = 0;
+		out++;
 	}
-	cpuc->lbr_stack.nr = i;
+	cpuc->lbr_stack.nr = out;
 }
 
 void intel_pmu_lbr_read(void)