[Fix] Fix crashes when socket write errors occur

contrib/librdns/resolver.c

@@ -402,6 +402,8 @@ rdns_process_timer (void *arg)
 		if (!renew) {
 			req->async->del_timer (req->async->data,
 					req->async_event);
+			req->async_event = NULL;
+			HASH_DEL (req->io->requests, req);
 		}
 
 		/* We have not scheduled timeout actually due to send error */
@@ -480,6 +482,7 @@ rdns_process_retransmit (int fd, void *arg)
 
 	resolver->async->del_write (resolver->async->data,
 			req->async_event);
+	req->async_event = NULL;
 
 	r = rdns_send_request (req, fd, false);
 

contrib/librdns/util.c

@@ -409,12 +409,16 @@ rdns_request_free (struct rdns_request *req)
 						req->async_event);
 				/* Remove from id hashes */
 				HASH_DEL (req->io->requests, req);
+				req->async_event = NULL;
 			}
 			else if (req->state == RDNS_REQUEST_WAIT_SEND) {
 				/* Remove retransmit event */
 				req->async->del_write (req->async->data,
 						req->async_event);
+				HASH_DEL (req->io->requests, req);
+				req->async_event = NULL;
 			}
+
 		}
 #ifdef TWEETNACL
 		if (req->curve_plugin_data != NULL) {