diff --git a/src/acl.c b/src/acl.c
index e8d4dc3..95b559c 100644
--- a/src/acl.c
+++ b/src/acl.c
@@ -251,6 +251,7 @@
 					memprintf(err, "in argument to '%s', %s", expr->kw, *err);
 					goto out_free_expr;
 				}
+				arg = end;
 			}
 			else if (ARGM(expr->smp->fetch->arg_mask) == 1) {
 				int type = (expr->smp->fetch->arg_mask >> 4) & 15;
@@ -308,7 +309,10 @@
 		 */
 
 		/* look for the begining of the converters list */
-		arg = strchr(args[0], ',');
+		if (arg)
+			arg = strchr(arg, ',');
+		else
+			arg = strchr(args[0], ',');
 		if (arg) {
 			prev_type = expr->smp->fetch->out_type;
 			while (1) {