Index: main/pbx.c
===================================================================
--- main/pbx.c	(revision 60173)
+++ main/pbx.c	(working copy)
@@ -1642,7 +1642,13 @@
 			parse_variable_name(vars, &offset, &offset2, &isfunction);
 			if (isfunction) {
 				/* Evaluate function */
-				cp4 = ast_func_read(c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
+				if (c)
+					cp4 = ast_func_read(c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
+				else {
+					struct ast_channel c = { 0, };
+					memcpy(&c.varshead, headp, sizeof(c.varshead));
+					cp4 = ast_func_read(&c, vars, workspace, VAR_BUF_SIZE) ? NULL : workspace;
+				}
 
 				if (option_debug)
 					ast_log(LOG_DEBUG, "Function result is '%s'\n", cp4 ? cp4 : "(null)");