call_user_function() sets GLOBAL(function_state).function_name to p_function_name.value.str.val and passes same p_function_name as parameter to cs_functioncall_pre_variable_passing() witch pushes function_state to function_state_stack and sets its parameter to GLOBAL(function_state).function_name. This results situration where there is 2 references to p_function_name.value.str.val: in function_state and function_state_stack top element OR if user abort is done in deeper level, 2 consecutive function_state_stack elements
This will result in crash php3_request_shutdown() when same pointer is freed twice

Possible fix:
diff -n -r1.1 language-parser.y
d742 1
a742 1
        pval p_function_name,dummy_function_name;
a760 2
        dummy_function_name = p_function_name;
        pval_copy_constructor(&dummy_function_name);
d770 1
a770 1
        GLOBAL(function_state).function_name = dummy_function_name.value.str.val;
a789 1
        pval_destructor(&dummy_function_name);

I don't think it is best one, but it works