Merge branch '3079-always-enqueue-isc__nm_tcp_resumeread' into 'main'

Always enqueue isc__nm_tcp_resumeread()

Closes #3079

See merge request isc-projects/bind9!5695

CHANGES

@@ -1,3 +1,8 @@
+5790.	[bug]		Enforce enqueuing TCP resumeread to prevent the
+			next read callback from being executed before the
+			current read callback has finished, and the worker
+			receive buffer has been marked as "freed". [GL #3079]
+
 5789.	[bug]		Allow replacing expired zone signatures with
 			signatures created by the KSK. [GL #3049]
 

doc/notes/notes-current.rst

@@ -53,3 +53,7 @@ Bug Fixes
   version of the zone, preventing resynchronization of zone contents
   after ``named`` restart in case the unsigned zone file gets modified
   while ``named`` is not running. This has been fixed. :gl:`#3071`
+
+- Under certain circumstances, reading from the raw TCP channels used
+  for rndc and statistics could cause assertion failure.  This has been
+  fixed. :gl:`#3079`

lib/isc/netmgr/tcp.c

@@ -814,6 +814,7 @@ isc__nm_tcp_resumeread(isc_nmhandle_t *handle) {
 
 	isc__netievent_tcpstartread_t *ievent = NULL;
 	isc_nmsocket_t *sock = handle->sock;
+	isc__networker_t *worker = &sock->mgr->workers[sock->tid];
 
 	REQUIRE(sock->tid == isc_nm_tid());
 
@@ -835,8 +836,18 @@ isc__nm_tcp_resumeread(isc_nmhandle_t *handle) {
 
 	ievent = isc__nm_get_netievent_tcpstartread(sock->mgr, sock);
 
-	isc__nm_maybe_enqueue_ievent(&sock->mgr->workers[sock->tid],
-				     (isc__netievent_t *)ievent);
+	if (worker->recvbuf_inuse) {
+		/*
+		 * If we happen to call the resumeread from inside the receive
+		 * callback, the worker->recvbuf might still be in use, so we
+		 * need to force enqueue the next read event.
+		 */
+		isc__nm_enqueue_ievent(worker, (isc__netievent_t *)ievent);
+
+	} else {
+		isc__nm_maybe_enqueue_ievent(worker,
+					     (isc__netievent_t *)ievent);
+	}
 }
 
 void