void re_yypush_buffer_state (YY_BUFFER_STATE new_buffer , yyscan_t yyscanner)
{
    struct yyguts_t * yyg = (struct yyguts_t*)yyscanner;
	if (new_buffer == NULL)
		return;

	re_yyensure_buffer_stack(yyscanner);

	/* This block is copied from re_yy_switch_to_buffer. */
	if ( YY_CURRENT_BUFFER )
		{
		/* Flush out information for old buffer. */
		*yyg->yy_c_buf_p = yyg->yy_hold_char;
		YY_CURRENT_BUFFER_LVALUE->yy_buf_pos = yyg->yy_c_buf_p;
		YY_CURRENT_BUFFER_LVALUE->yy_n_chars = yyg->yy_n_chars;
		}

	/* Only push if top exists. Otherwise, replace top. */
	if (YY_CURRENT_BUFFER)
		yyg->yy_buffer_stack_top++;
	YY_CURRENT_BUFFER_LVALUE = new_buffer;

	/* copied from re_yy_switch_to_buffer. */
	re_yy_load_buffer_state(yyscanner );
	yyg->yy_did_buffer_switch_on_eof = 1;
}

The product dereferences a pointer that it expects to be valid but is NULL.