perf trace: Do not show syscall tracepoint filter in the --no-syscalls case

We were accessing trace->syscalls.events members even when that struct
wasn't initialized, i.e. --no-syscalls was specified on the command
line, fix it to show that, still in debug mode, when we have an event
qualifier list, i.e. when we actually are doing subset syscall tracing.

Cc: Adrian Hunter <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: David Ahern <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Milian Wolff <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Stephane Eranian <[email protected]>
Fixes: 19867b6186f3 ("perf trace: Use event filters for the event qualifier list")
Link: http://lkml.kernel.org/n/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 3 insertions, 2 deletions

diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
index 06cfa93c0305..3cfca93309ee 100644
--- a/tools/perf/builtin-trace.c
+++ b/tools/perf/builtin-trace.c
@@ -2394,9 +2394,10 @@ static int trace__run(struct trace *trace, int argc, const char **argv)
 		err = trace__set_ev_qualifier_filter(trace);
 		if (err < 0)
 			goto out_errno;
-	}
 
-	pr_debug("%s\n", trace->syscalls.events.sys_exit->filter);
+		pr_debug("event qualifier tracepoint filter: %s\n",
+			 trace->syscalls.events.sys_exit->filter);
+	}
 
 	err = perf_evlist__apply_filters(evlist, &evsel);
 	if (err < 0)