[tip:perf/urgent] perf record: Fix s390 undefined record__auxtrace_init() return value

[tip-bot for Thomas Richter <tipbot@zytor.com>]

Commit-ID:  5d9946c3e5e38e07ab7019db9413a96807a325f2
Gitweb:     https://git.kernel.org/tip/5d9946c3e5e38e07ab7019db9413a96807a325f2
Author:     Thomas Richter <tmricht@linux.ibm.com>
AuthorDate: Mon, 23 Apr 2018 16:29:40 +0200
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Mon, 23 Apr 2018 12:05:02 -0300

perf record: Fix s390 undefined record__auxtrace_init() return value

Command 'perf record' calls:

  cmd_report()
    record__auxtrace_init()
       auxtrace_record__init()

On s390 function auxtrace_record__init() returns random return value due
to missing initialization.

This sometime causes 'perf record' to exit immediately without error
message and creating a perf.data file.

Fix this by setting error the return code to zero before returning from
platform specific functions which may not set the error code in call
cases.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180423142940.21143-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/arch/s390/util/auxtrace.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/arch/s390/util/auxtrace.c b/tools/perf/arch/s390/util/auxtrace.c
index 6cb48e4cffd9..3afe8256eff2 100644
--- a/tools/perf/arch/s390/util/auxtrace.c
+++ b/tools/perf/arch/s390/util/auxtrace.c
@@ -87,6 +87,7 @@ struct auxtrace_record *auxtrace_record__init(struct perf_evlist *evlist,
 	struct perf_evsel *pos;
 	int diagnose = 0;
 
+	*err = 0;
 	if (evlist->nr_entries == 0)
 		return NULL;