[tip:perf/urgent] perf evlist: Check that there is a thread_map when preparing a workload

[tip-bot for Arnaldo Carvalho de Melo <tipbot@zytor.com>]

Commit-ID:  1aaf63b1ee912abd7675681f9d6ffaaf2ffc0451
Gitweb:     http://git.kernel.org/tip/1aaf63b1ee912abd7675681f9d6ffaaf2ffc0451
Author:     Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Fri, 10 Oct 2014 14:29:49 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Tue, 14 Oct 2014 17:32:53 -0300

perf evlist: Check that there is a thread_map when preparing a workload

The perf_evlist__prepare_workload expects a thread map to be in place
so that it can store the pid of the workload being started, so check it
and tell the developer about it instead of segfaulting.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jean Pihet <jean.pihet@linaro.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-jvlz2f264e7kpmhjmwltikqw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/evlist.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 3cebc9a..5fc7bd4 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -1276,8 +1276,14 @@ int perf_evlist__prepare_workload(struct perf_evlist *evlist, struct target *tar
 		sigaction(SIGUSR1, &act, NULL);
 	}
 
-	if (target__none(target))
+	if (target__none(target)) {
+		if (evlist->threads == NULL) {
+			fprintf(stderr, "FATAL: evlist->threads need to be set at this point (%s:%d).\n",
+				__func__, __LINE__);
+			goto out_close_pipes;
+		}
 		evlist->threads->map[0] = evlist->workload.pid;
+	}
 
 	close(child_ready_pipe[1]);
 	close(go_pipe[0]);