Comment 20 for bug 1954854

From the 114 crash file:

(gdb) bt
#0 isc__nm_tcp_send (handle=0x7eff7522dbb0, region=0x7eff7d39a9b8, cb=0x7eff887675a0 <tcpdnssend_cb>,
    cbarg=0x7eff7d39a9a8) at tcp.c:852
#1 0x00007eff88a2e707 in client_sendpkg (client=client@entry=0x7eff754c31b0, buffer=<optimized out>,
    buffer=<optimized out>) at client.c:331
#2 0x00007eff88a2ffe9 in ns_client_send (client=client@entry=0x7eff754c31b0) at client.c:592
#3 0x00007eff88a3e9b0 in query_send (client=0x7eff754c31b0) at query.c:552
#4 0x00007eff88a469a7 in ns_query_done (qctx=qctx@entry=0x7eff85476850) at query.c:10914
#5 0x00007eff88a4dde6 in query_respond (qctx=0x7eff85476850) at query.c:7407
#6 query_prepresponse (qctx=qctx@entry=0x7eff85476850) at query.c:9906
#7 0x00007eff88a49936 in query_gotanswer (qctx=qctx@entry=0x7eff85476850, res=res@entry=0) at query.c:6823
#8 0x00007eff88a4f4c6 in query_resume (qctx=0x7eff85476850) at query.c:6121
#9 fetch_callback (task=<optimized out>, event=<optimized out>) at query.c:5703
#10 0x00007eff88770fa1 in dispatch (threadid=<optimized out>, manager=<optimized out>) at task.c:1152
#11 run (queuep=<optimized out>) at task.c:1344
#12 0x00007eff88239609 in start_thread (arg=<optimized out>) at pthread_create.c:477
#13 0x00007eff8815a293 in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

(gdb) list tcp.c:852
file: "src/unix/tcp.c", line number: 852, symbol: "???"
847 src/unix/tcp.c: No such file or directory.
file: "tcp.c", line number: 852, symbol: "???"
847 void *cbarg) {
848 isc_nmsocket_t *sock = handle->sock;
849 isc__netievent_tcpsend_t *ievent = NULL;
850 isc__nm_uvreq_t *uvreq = NULL;
851
852 REQUIRE(sock->type == isc_nm_tcpsocket);
853
854 uvreq = isc__nm_uvreq_get(sock->mgr, sock);
855 uvreq->uvbuf.base = (char *)region->base;
856 uvreq->uvbuf.len = region->length;
(gdb)

(gdb) print sock
$1 = (isc_nmsocket_t *) 0x0
(gdb) print sock->mgr
Cannot access memory at address 0x10