interfacemgr shutdown race

Job #1748465 failed for 80ca95a9:

WARNING: ThreadSanitizer: data race 
  Write of size 8 at 0x000000000001 by thread T1 (mutexes: write M1):
    #0 memset <null>
    #1 memset /usr/include/x86_64-linux-gnu/bits/string_fortified.h:71:10
    #2 mem_put lib/isc/mem.c:361:3
    #3 isc__mem_free lib/isc/mem.c:1012:2
    #4 isc__mem_put lib/isc/mem.c:777:3
    #5 ns_interface_destroy lib/ns/interfacemgr.c:713:2
    #6 ns_interface_detach lib/ns/interfacemgr.c:730:3
    #7 purge_old_interfaces lib/ns/interfacemgr.c:770:4
    #8 ns_interfacemgr_shutdown lib/ns/interfacemgr.c:401:2
    #9 shutdown_server bin/named/server.c:10086:2
    #10 task_run lib/isc/task.c:816:5
    #11 isc_task_run lib/isc/task.c:896:10
    #12 isc__nm_async_task lib/isc/netmgr/netmgr.c:863:11
    #13 process_netievent lib/isc/netmgr/netmgr.c:942:3
    #14 process_queue lib/isc/netmgr/netmgr.c:1032:16
    #15 process_all_queues lib/isc/netmgr/netmgr.c:783:25
    #16 async_cb lib/isc/netmgr/netmgr.c:812:6
    #17 <null> <null>
    #18 isc__trampoline_run lib/isc/trampoline.c:184:11

  Previous read of size 8 at 0x000000000001 by thread T2:
    #0 memmove <null>
    #1 isc___nmhandle_get lib/isc/netmgr/netmgr.c
    #2 isc__nm_get_read_req lib/isc/netmgr/netmgr.c:2130:18
    #3 isc__nm_tcpdns_processbuffer lib/isc/netmgr/tcpdns.c:787:8
    #4 processbuffer lib/isc/netmgr/netmgr.c:2257:11
    #5 isc__nm_process_sock_buffer lib/isc/netmgr/netmgr.c:2282:25
    #6 isc__nm_resume_processing lib/isc/netmgr/netmgr.c:2338:2
    #7 nmhandle_detach_cb lib/isc/netmgr/netmgr.c:1864:4
    #8 isc__nmhandle_detach lib/isc/netmgr/netmgr.c:1804:3
    #9 isc___nm_uvreq_put lib/isc/netmgr/netmgr.c:2462:3
    #10 isc__nm_async_sendcb lib/isc/netmgr/netmgr.c:2748:2
    #11 process_netievent lib/isc/netmgr/netmgr.c:994:3
    #12 process_queue lib/isc/netmgr/netmgr.c:1032:16
    #13 process_all_queues lib/isc/netmgr/netmgr.c:783:25
    #14 async_cb lib/isc/netmgr/netmgr.c:812:6
    #15 <null> <null>
    #16 isc__trampoline_run lib/isc/trampoline.c:184:11

  Location is heap block of size 1392 at 0x000000000032 allocated by thread T1:
    #0 malloc <null>
    #1 default_memalloc lib/isc/mem.c:411:8
    #2 mem_get lib/isc/mem.c:343:8
    #3 mem_allocateunlocked lib/isc/mem.c:918:7
    #4 isc__mem_allocate lib/isc/mem.c:935:7
    #5 isc__mem_get lib/isc/mem.c:740:11
    #6 ns_interface_create lib/ns/interfacemgr.c:412:8
    #7 ns_interface_setup lib/ns/interfacemgr.c:599:11
    #8 do_scan lib/ns/interfacemgr.c:1199:14
    #9 ns_interfacemgr_scan0 lib/ns/interfacemgr.c:1258:11
    #10 ns_interfacemgr_scan lib/ns/interfacemgr.c:1306:11
    #11 load_configuration bin/named/server.c:9110:11
    #12 run_server bin/named/server.c:10054:2
    #13 task_run lib/isc/task.c:816:5
    #14 isc_task_run lib/isc/task.c:896:10
    #15 isc__nm_async_task lib/isc/netmgr/netmgr.c:863:11
    #16 process_netievent lib/isc/netmgr/netmgr.c:942:3
    #17 process_queue lib/isc/netmgr/netmgr.c:1032:16
    #18 process_all_queues lib/isc/netmgr/netmgr.c:783:25
    #19 async_cb lib/isc/netmgr/netmgr.c:812:6
    #20 <null> <null>
    #21 isc__trampoline_run lib/isc/trampoline.c:184:11

  Mutex M1 is already destroyed.

  Thread T1 (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/pthreads/thread.c:79:8
    #2 isc__netmgr_create lib/isc/netmgr/netmgr.c:347:3
    #3 isc_managers_create lib/isc/managers.c:39:2
    #4 create_managers bin/named/main.c:941:11
    #5 setup bin/named/main.c:1216:11
    #6 main bin/named/main.c:1507:2

  Thread T2 (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/pthreads/thread.c:79:8
    #2 isc__netmgr_create lib/isc/netmgr/netmgr.c:347:3
    #3 isc_managers_create lib/isc/managers.c:39:2
    #4 create_managers bin/named/main.c:941:11
    #5 setup bin/named/main.c:1216:11
    #6 main bin/named/main.c:1507:2

SUMMARY: ThreadSanitizer: data race in memset