diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index f588cce60194..a550f030b85d 100644
--- a/tools/perf/util/pmu.c
+++ b/tools/perf/util/pmu.c
@@ -314,7 +314,7 @@ static int perf_pmu__parse_scale(struct perf_pmu *pmu, struct perf_pmu_alias *al
 		goto error;
 
 	sret = read(fd, scale, sizeof(scale)-1);
-	if (sret < 0)
+	if (sret <= 0)
 		goto error;
 
 	if (scale[sret - 1] == '\n')
@@ -346,7 +346,7 @@ static int perf_pmu__parse_unit(struct perf_pmu *pmu, struct perf_pmu_alias *ali
 		return -1;
 
 	sret = read(fd, alias->unit, UNIT_MAX_LEN);
-	if (sret < 0)
+	if (sret <= 0)
 		goto error;
 
 	close(fd);