[PATCH AUTOSEL 6.3 04/17] tracing/user_events: Handle matching arguments that is null from dyn_events

[Sasha Levin]

From: sunliming <sunliming@xxxxxxxxxx>

[ Upstream commit cfac4ed7279d056df6167bd665e460787dc9e0c4 ]

When A registering user event from dyn_events has no argments, it will pass the
matching check, regardless of whether there is a user event with the same name
and arguments. Add the matching check when the arguments of registering user
event is null.

Link: https://lore.kernel.org/linux-trace-kernel/20230529065110.303440-1-sunliming@xxxxxxxxxx

Signed-off-by: sunliming <sunliming@xxxxxxxxxx>
Acked-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 kernel/trace/trace_events_user.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/trace/trace_events_user.c b/kernel/trace/trace_events_user.c
index 774d146c2c2ca..ad64da21c34aa 100644
--- a/kernel/trace/trace_events_user.c
+++ b/kernel/trace/trace_events_user.c
@@ -1232,6 +1232,8 @@ static bool user_event_match(const char *system, const char *event,
 
 	if (match && argc > 0)
 		match = user_fields_match(user, argc, argv);
+	else if (match && argc == 0)
+		match = list_empty(&user->fields);
 
 	return match;
 }
-- 
2.39.2