Index: linux-2.6/arch/x86/kernel/cpu/perf_event.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/cpu/perf_event.c
+++ linux-2.6/arch/x86/kernel/cpu/perf_event.c
@@ -383,14 +383,13 @@
 
 static bool check_hw_exists(void)
 {
-	u64 val, val_new;
-
+	u64 val, val_new = 0;
+	int ret = 0;
 	val = 0xabcdUL;
-	(void) checking_wrmsrl(x86_pmu.perfctr, val);
-	rdmsrl_safe(x86_pmu.perfctr, &val_new);
-	if (val != val_new)
+	ret |= checking_wrmsrl(x86_pmu.perfctr, val);
+	ret |= rdmsrl_safe(x86_pmu.perfctr, &val_new);
+	if (ret || val != val_new)
 		return false;
-
 	return true;
 }