ThreadSanitizer: data race in __interceptor_memcmp & __interceptor_memset

Job #2428973 failed for 4d57ef0c in the doth system test:

WARNING: ThreadSanitizer: data race 
  Read of size 8 at 0x000000000001 by thread T1:
    #0 memcmp <null>
    #1 ASN1_STRING_cmp <null>
    #2 isc__nm_tlsdns_read_cb netmgr/tlsdns.c:1409
    #3 uv__read /usr/src/libuv-v1.43.0/src/unix/stream.c:1247
    #4 isc__trampoline_run lib/isc/trampoline.c:187

  Previous write of size 8 at 0x000000000001 by thread T2 (mutexes: write M1):
    #0 malloc <null>
    #1 ASN1_STRING_set <null>
    #2 isc__nm_tlsdns_read_cb netmgr/tlsdns.c:1409
    #3 uv__read /usr/src/libuv-v1.43.0/src/unix/stream.c:1247
    #4 isc__trampoline_run lib/isc/trampoline.c:187

  Location is heap block of size 21 at 0x000000000001 allocated by thread T2:
    #0 malloc <null>
    #1 ASN1_STRING_set <null>
    #2 isc__nm_tlsdns_read_cb netmgr/tlsdns.c:1409
    #3 uv__read /usr/src/libuv-v1.43.0/src/unix/stream.c:1247
    #4 isc__trampoline_run lib/isc/trampoline.c:187

  Mutex M1 (0x000000000009) created at:
    #0 pthread_rwlock_init <null>
    #1 CRYPTO_THREAD_lock_new <null>
    #2 listenelt_create lib/ns/listenlist.c:73
    #3 ns_listenelt_create lib/ns/listenlist.c:193
    #4 listenelt_fromconfig bin/named/server.c:11127
    #5 listenlist_fromconfig bin/named/server.c:10863
    #6 load_configuration bin/named/server.c:8895
    #7 run_server bin/named/server.c:9835
    #8 task_run lib/isc/task.c:711
    #9 isc_task_run lib/isc/task.c:791
    #10 isc__nm_async_task netmgr/netmgr.c:782
    #11 process_netievent netmgr/netmgr.c:853
    #12 process_queue netmgr/netmgr.c:944
    #13 process_all_queues netmgr/netmgr.c:716
    #14 async_cb netmgr/netmgr.c:745
    #15 uv__async_io /usr/src/libuv-v1.43.0/src/unix/async.c:163
    #16 isc__trampoline_run lib/isc/trampoline.c:187

  Thread T1 (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/thread.c:81
    #2 isc__netmgr_create netmgr/netmgr.c:291
    #3 isc_managers_create lib/isc/managers.c:31
    #4 create_managers bin/named/main.c:920
    #5 setup bin/named/main.c:1184
    #6 main bin/named/main.c:1452

  Thread T2 (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/thread.c:81
    #2 isc__netmgr_create netmgr/netmgr.c:291
    #3 isc_managers_create lib/isc/managers.c:31
    #4 create_managers bin/named/main.c:920
    #5 setup bin/named/main.c:1184
    #6 main bin/named/main.c:1452

SUMMARY: ThreadSanitizer: data race in __interceptor_memcmp