tracing/probe: Check event/group naming rule at parsing

Check event and group naming rule at parsing it instead
of allocating probes.

Link: http://lkml.kernel.org/r/155253784064.14922.2336893061156236237.stgit@devnote2

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_probe.c b/kernel/trace/trace_probe.c
index bf9d3d7..8f8411e 100644
--- a/kernel/trace/trace_probe.c
+++ b/kernel/trace/trace_probe.c
@@ -172,6 +172,10 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 			return -E2BIG;
 		}
 		strlcpy(buf, event, slash - event + 1);
+		if (!is_good_name(buf)) {
+			pr_info("Group name must follow the same rules as C identifiers\n");
+			return -EINVAL;
+		}
 		*pgroup = buf;
 		*pevent = slash + 1;
 		event = *pevent;
@@ -184,6 +188,10 @@ int traceprobe_parse_event_name(const char **pevent, const char **pgroup,
 		pr_info("Event name is too long\n");
 		return -E2BIG;
 	}
+	if (!is_good_name(event)) {
+		pr_info("Event name must follow the same rules as C identifiers\n");
+		return -EINVAL;
+	}
 	return 0;
 }