On Thu, 8 Feb 2018 19:18:18 +0900
Namhyung Kim [off-list ref] wrote:
						call->event.type,

quoted

@@ -150,6 +310,15 @@ static void func_event_trace(struct trace_event_file *trace_file,
 	entry = ring_buffer_event_data(event);
 	entry->ip = ip;
 	entry->parent_ip = parent_ip;
+	nr_args = arch_get_func_args(pt_regs, 0, func_event->arg_cnt, args);
+
+	list_for_each_entry(arg, &func_event->args, list) {
+		if (i < nr_args)
+			val = args[i];
+		else
+			val = 0;
+		memcpy(&entry->data[arg->offset], &val, arg->size);
+	}  

Where is the 'i' increased?

Good question. I think the increment got nuked via one of my rebases,
and then most my testing happened at the end of the patch series where
"i" is no longer used. But that's no excuse for keeping this bug
around. I'll fix it and test again at each patch.

Thanks for reporting.

-- Steve