[tip:perf/core] perf machine: Return NULL instead of null-terminating /proc/version array

[tip-bot for Donald Yandt]

Commit-ID:  34b65affe18daad31fed83e50d1f3b817786a2b7
Gitweb:     https://git.kernel.org/tip/34b65affe18daad31fed83e50d1f3b817786a2b7
Author:     Donald Yandt <donald.yandt@xxxxxxxxx>
AuthorDate: Tue, 28 May 2019 09:41:28 -0400
Committer:  Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitDate: Tue, 28 May 2019 18:37:44 -0300

perf machine: Return NULL instead of null-terminating /proc/version array

Return NULL instead of null-terminating version char array when fgets
fails due to end-of-file or error.

Signed-off-by: Donald Yandt <donald.yandt@xxxxxxxxx>
Cc: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Yanmin Zhang <yanmin_zhang@xxxxxxxxxxxxxxx>
Fixes: 30ba5b0e66c8 ("perf machine: Null-terminate version char array upon fgets(/proc/version) error")
Link: http://lkml.kernel.org/r/20190528134128.30841-1-donald.yandt@xxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
 tools/perf/util/machine.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index f5569f005cf3..17eec39e775e 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -1241,9 +1241,9 @@ static char *get_kernel_version(const char *root_dir)
 		return NULL;
 
 	tmp = fgets(version, sizeof(version), file);
-	if (!tmp)
-		*version = '\0';
 	fclose(file);
+	if (!tmp)
+		return NULL;
 
 	name = strstr(version, prefix);
 	if (!name)