ThreadSanitizer: data race lib/isc/unix/socket.c:1839:2 in destroy

WARNING: ThreadSanitizer: data race
  Read of size 8 at 0x000000000001 by thread T1:
    #0 destroy lib/isc/unix/socket.c:1839:2
    #1 process_fd lib/isc/unix/socket.c:3177:3
    #2 process_fds lib/isc/unix/socket.c:3257:3
    #3 netthread lib/isc/unix/socket.c:3503:10

  Previous write of size 8 at 0x000000000001 by thread T2 (mutexes: write M1, write M2):
    #0 send_recvdone_event lib/isc/unix/socket.c
    #1 isc_socket_cancel lib/isc/unix/socket.c:5053:5
    #2 dns_dispatch_detach lib/dns/dispatch.c:2985:4
    #3 fctx_cancelquery lib/dns/resolver.c:1378:3
    #4 rctx_done lib/dns/resolver.c:9478:3
    #5 resquery_response lib/dns/resolver.c
    #6 dispatch lib/isc/task.c:1136:7
    #7 run lib/isc/task.c:1323:2

  Location is heap block of size 361 at 0x000000000014 allocated by thread T2:
    #0 malloc <null>
    #1 default_memalloc lib/isc/mem.c:685:8
    #2 mem_get lib/isc/mem.c:598:8
    #3 isc___mem_get lib/isc/mem.c:1013:9
    #4 isc__mem_get lib/isc/mem.c:2365:10
    #5 allocate_socket lib/isc/unix/socket.c:1876:9
    #6 socket_create lib/isc/unix/socket.c:2450:11
    #7 isc_socket_create lib/isc/unix/socket.c:2535:10
    #8 fctx_query lib/dns/resolver.c:2044:12
    #9 rctx_resend lib/dns/resolver.c:9376:11
    #10 rctx_done lib/dns/resolver.c:9497:3
    #11 resquery_response lib/dns/resolver.c
    #12 dispatch lib/isc/task.c:1136:7
    #13 run lib/isc/task.c:1323:2

  Mutex M1 is already destroyed.

  Mutex M2 (0x000000000026) created at:
    #0 pthread_mutex_init <null>
    #1 isc__mutex_init lib/isc/pthreads/mutex.c:284:8
    #2 allocate_socket lib/isc/unix/socket.c:1913:2
    #3 socket_create lib/isc/unix/socket.c:2450:11
    #4 isc_socket_create lib/isc/unix/socket.c:2535:10
    #5 fctx_query lib/dns/resolver.c:2044:12
    #6 rctx_resend lib/dns/resolver.c:9376:11
    #7 rctx_done lib/dns/resolver.c:9497:3
    #8 resquery_response lib/dns/resolver.c
    #9 dispatch lib/isc/task.c:1136:7
    #10 run lib/isc/task.c:1323:2

  Thread T2 'isc-socket-0' (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/pthreads/thread.c:75:8
    #2 isc_socketmgr_create2 lib/isc/unix/socket.c:3817:3
    #3 isc_socketmgr_create lib/isc/unix/socket.c:3774:10
    #4 isc_socketmgr_createinctx lib/isc/unix/socket.c:5561:11
    #5 main bin/delv/delv.c:1731:2

  Thread T2 (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/pthreads/thread.c:75:8
    #2 isc_taskmgr_create lib/isc/task.c:1414:3
    #3 isc_taskmgr_createinctx lib/isc/task.c:1982:11
    #4 main bin/delv/delv.c:1730:2

SUMMARY: ThreadSanitizer: data race lib/isc/unix/socket.c:1839:2 in destroy