perf symbols: Do not open device files

The dso__read_binary_type_filename gets the dso's file name to open. We
need to check it for regular file before trying to open it, otherwise we
might get stuck with device file.
Signed-off-by: NJiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <andi@firstfloor.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Don Zickus <dzickus@redhat.com>
Cc: Joe Mario <jmario@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20160920161245.GA8995@kravaSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/dso.c

@@ -363,6 +363,9 @@ static int __open_dso(struct dso *dso, struct machine *machine)
 		return -EINVAL;
 	}
 
+	if (!is_regular_file(name))
+		return -EINVAL;
+
 	fd = do_open(name);
 	free(name);
 	return fd;