Merge v7.1.5linux-rolling-stable

Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 8 insertions, 2 deletions

diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
index 23337d2fa281..64544e1e6810 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);
@@ -865,6 +865,12 @@ static char *pmu_id(const char *name)
 	if (filename__read_str(path, &str, &len) < 0)
 		return NULL;
 
+	/* empty identifier file — nothing useful */
+	if (len == 0) {
+		free(str);
+		return NULL;
+	}
+
 	str[len - 1] = 0; /* remove line feed */
 
 	return str;