On Tue, 13 Feb 2018 00:47:50 +0900
Masami Hiramatsu [off-list ref] wrote:

quoted

quoted

 		if (WARN_ON(!fevent->last_arg))
 			break;
-		ret = kstrtoul(token, 0, &val);
-		if (ret < 0)
-			break;
+		if (isalpha(token[0]) || token[0] != '_') {  

I guess you wanted the token[0] being '_'.  Maybe it'd be better adding

  #define isident0(x)  (isalpha(x) || (x) == '_')  

If this '$' is only for the symbol or direct address(with 0x prefix),
you just need to check by !isdigit(token[0]), isn't it? 
(and if it is insane get_symbol just fails)

I modified a lot of this code for the next version (which I'm still
tweaking).

I have this for next_token() (which I may add for the
trace_events_filter.c code as Al Viro has recently pointed out issues
with its parsing):

static char *next_token(char **ptr, char *last)
{
	char *arg;
	char *str;

	if (!*ptr)
		return NULL;

	arg = *ptr;

	if (*last)
		*arg = *last;

	if (!*arg)
		return NULL;

	for (str = arg; *str; str++) {
		if (!isalnum(*str) && *str != '_')
			break;
	}
	if (*str) {
		if (str == arg)
			str++;
		*last = *str;
		*str = 0;
		*ptr = str;
		return arg;
	}

	*last = 0;
	*ptr = NULL;
	return arg;
}


And this:

static bool valid_name(const char *token)
{
	return isalpha(token[0]) || token[0] == '_';
}

As all tokens will now be either entirely alphanumeric with '_' or a
single character.

-- Steve