trace: use override credential guard

Use override credential guards for scoped credential override with
automatic restoration on scope exit.

Link: https://patch.msgid.link/20251103-work-creds-guards-prepare_creds-v1-12-b447b82f2c9b@kernel.org
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>

Author: brauner

kernel/trace/trace_events_user.c

@@ -1449,9 +1449,6 @@ static struct trace_event_functions user_event_funcs = {
 
 static int user_event_set_call_visible(struct user_event *user, bool visible)
 {
-	int ret;
-	const struct cred *old_cred;
-
 	CLASS(prepare_creds, cred)();
 	if (!cred)
 		return -ENOMEM;
@@ -1467,16 +1464,12 @@ static int user_event_set_call_visible(struct user_event *user, bool visible)
 	 */
 	cred->fsuid = GLOBAL_ROOT_UID;
 
-	old_cred = override_creds(cred);
-
-	if (visible)
-		ret = trace_add_event_call(&user->call);
-	else
-		ret = trace_remove_event_call(&user->call);
+	scoped_with_creds(cred) {
+		if (visible)
+			return trace_add_event_call(&user->call);
 
-	revert_creds(old_cred);
-
-	return ret;
+		return trace_remove_event_call(&user->call);
+	}
 }
 
 static int destroy_user_event(struct user_event *user)