perf record: Delay setting the header writing atexit call

While testing the --filter option I noticed that we were writing lots of
unneeded stuff to the perf.data header when the filter ioctl fails, so
move the atexit(atexit_header) call to after we create the counters
successfully.

Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-record.c

@@ -538,11 +538,6 @@ static int __cmd_record(int argc, const char **argv)
 	if (have_tracepoints(&evsel_list->entries))
 		perf_header__set_feat(&session->header, HEADER_TRACE_INFO);
 
-	/*
- 	 * perf_session__delete(session) will be called at atexit_header()
-	 */
-	atexit(atexit_header);
-
 	if (forks) {
 		child_pid = fork();
 		if (child_pid < 0) {
@@ -601,6 +596,11 @@ static int __cmd_record(int argc, const char **argv)
 
 	perf_session__set_sample_type(session, sample_type);
 
+	/*
+	 * perf_session__delete(session) will be called at atexit_header()
+	 */
+	atexit(atexit_header);
+
 	if (pipe_output) {
 		err = perf_header__write_pipe(output);
 		if (err < 0)