diff --git a/tools/power/cpupower/lib/cpuidle.c b/tools/power/cpupower/lib/cpuidle.c
index f72ba7fd5ae2..60cd5b34ffdf 100644
--- a/tools/power/cpupower/lib/cpuidle.c
+++ b/tools/power/cpupower/lib/cpuidle.c
@@ -149,6 +149,7 @@ unsigned long long cpuidle_state_get_one_value(unsigned int cpu,
 	if (len == 0)
 		return 0;
 
+	errno = 0;
 	value = strtoull(linebuf, &endp, 0);
 
 	if (endp == linebuf || errno == ERANGE)