Under these circumstances, the connection hasn't been fully established
and smtp_connect hasn't been called, yet smtp_done still calls the state
machine which dereferences the NULL conn pointer in struct pingpong.
(void)premature;
- if(!smtp)
+ if(!smtp || !pp->conn)
/* When the easy handle is removed from the multi interface while libcurl
is still trying to resolve the host name, the SMTP struct is not yet
initialized. However, the removal action calls Curl_done() which in