[PATCH 4.18 25/34] tracing: Fix synthetic event to allow semicolon at end

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Masami Hiramatsu <mhiramat@kernel.org>

commit a360d9e4016c1fcf41553b37ad496870dc5723d0 upstream.

Fix synthetic event to allow independent semicolon at end.

The synthetic_events interface accepts a semicolon after the
last word if there is no space.

 # echo "myevent u64 var;" >> synthetic_events

But if there is a space, it returns an error.

 # echo "myevent u64 var ;" > synthetic_events
 sh: write error: Invalid argument

This behavior is difficult for users to understand. Let's
allow the last independent semicolon too.

Link: http://lkml.kernel.org/r/153986835420.18251.2191216690677025744.stgit@devbox

Cc: Shuah Khan <shuah@kernel.org>
Cc: Tom Zanussi <tom.zanussi@linux.intel.com>
Cc: stable@vger.kernel.org
Fixes: commit 4b147936fa50 ("tracing: Add support for 'synthetic' events")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 kernel/trace/trace_events_hist.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/kernel/trace/trace_events_hist.c
+++ b/kernel/trace/trace_events_hist.c
@@ -1097,7 +1097,7 @@ static int create_synth_event(int argc,
 		i += consumed - 1;
 	}
 
-	if (i < argc) {
+	if (i < argc && strcmp(argv[i], ";") != 0) {
 		ret = -EINVAL;
 		goto err;
 	}