ThreadSanitizer: data race /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1027 in nmhandle_free

WARNING: ThreadSanitizer: data race (pid=29181)
  Write of size 8 at 0x7b90000a0010 by thread T16 (mutexes: write M562522896233146464):
    #0 nmhandle_free /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1027 (libisc.so.1504+0x3e3b7)
    #1 nmhandle_deactivate /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1057 (libisc.so.1504+0x3e59f)
    #2 isc_nmhandle_unref /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1108 (libisc.so.1504+0x409f0)
    #3 fetch_callback /home/ondrej/Projects/bind9/lib/ns/query.c:5680 (libns.so.1502+0x46b71)
    #4 dispatch /home/ondrej/Projects/bind9/lib/isc/task.c:1134 (libisc.so.1504+0x56f36)
    #5 run /home/ondrej/Projects/bind9/lib/isc/task.c:1319 (libisc.so.1504+0x56f36)
    #6 <null> <null> (libtsan.so.0+0x29b3d)

  Previous read of size 4 at 0x7b90000a0010 by thread T1:
    #0 isc_nmhandle_unref /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1067 (libisc.so.1504+0x4091d)
    #1 isc__nm_uvreq_put /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1214 (libisc.so.1504+0x41bef)
    #2 udp_send_cb /home/ondrej/Projects/bind9/lib/isc/netmgr/udp.c:439 (libisc.so.1504+0x46c1d)
    #3 <null> <null> (libuv.so.1+0x1d283)
    #4 <null> <null> (libtsan.so.0+0x29b3d)

  Location is heap block of size 7489 at 0x7b90000a0000 allocated by thread T8:
    #0 malloc <null> (libtsan.so.0+0x2b1a3)
    #1 default_memalloc /home/ondrej/Projects/bind9/lib/isc/mem.c:685 (libisc.so.1504+0x33fee)
    #2 mem_get /home/ondrej/Projects/bind9/lib/isc/mem.c:598 (libisc.so.1504+0x34c7e)
    #3 mem_allocateunlocked /home/ondrej/Projects/bind9/lib/isc/mem.c:1222 (libisc.so.1504+0x34c7e)
    #4 isc___mem_allocate /home/ondrej/Projects/bind9/lib/isc/mem.c:1242 (libisc.so.1504+0x34c7e)
    #5 isc__mem_allocate /home/ondrej/Projects/bind9/lib/isc/mem.c:2387 (libisc.so.1504+0x3be64)
    #6 isc___mem_get /home/ondrej/Projects/bind9/lib/isc/mem.c:1007 (libisc.so.1504+0x3c6ca)
    #7 isc__mem_get /home/ondrej/Projects/bind9/lib/isc/mem.c:2365 (libisc.so.1504+0x3aef1)
    #8 alloc_handle /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:916 (libisc.so.1504+0x40547)
    #9 isc__nmhandle_get /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:940 (libisc.so.1504+0x40547)
    #10 udp_recv_cb /home/ondrej/Projects/bind9/lib/isc/netmgr/udp.c:312 (libisc.so.1504+0x46841)
    #11 <null> <null> (libuv.so.1+0x1d6d4)
    #12 <null> <null> (libtsan.so.0+0x29b3d)

  Mutex M562522896233146464 is already destroyed.

  Thread T16 'isc-worker0007' (tid=29211, running) created by main thread at:
    #0 pthread_create <null> (libtsan.so.0+0x2be1b)
    #1 isc_thread_create /home/ondrej/Projects/bind9/lib/isc/pthreads/thread.c:75 (libisc.so.1504+0x7bc54)
    #2 isc_taskmgr_create /home/ondrej/Projects/bind9/lib/isc/task.c:1410 (libisc.so.1504+0x59cf3)
    #3 create_managers main.c:902 (named+0x1aeec)
    #4 setup main.c:1235 (named+0x1aeec)
    #5 main main.c:1515 (named+0x1aeec)

  Thread T1 'isc-net-0000' (tid=29196, running) created by main thread at:
    #0 pthread_create <null> (libtsan.so.0+0x2be1b)
    #1 isc_thread_create /home/ondrej/Projects/bind9/lib/isc/pthreads/thread.c:75 (libisc.so.1504+0x7bc54)
    #2 isc_nm_start /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:149 (libisc.so.1504+0x3ec4a)
    #3 create_managers main.c:895 (named+0x1ae90)
    #4 setup main.c:1235 (named+0x1ae90)
    #5 main main.c:1515 (named+0x1ae90)

  Thread T8 'isc-net-0007' (tid=29203, running) created by main thread at:
    #0 pthread_create <null> (libtsan.so.0+0x2be1b)
    #1 isc_thread_create /home/ondrej/Projects/bind9/lib/isc/pthreads/thread.c:75 (libisc.so.1504+0x7bc54)
    #2 isc_nm_start /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:149 (libisc.so.1504+0x3ec4a)
    #3 create_managers main.c:895 (named+0x1ae90)
    #4 setup main.c:1235 (named+0x1ae90)
    #5 main main.c:1515 (named+0x1ae90)

SUMMARY: ThreadSanitizer: data race /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1027 in nmhandle_free

and

WARNING: ThreadSanitizer: data race (pid=29181)
  Write of size 8 at 0x7b90000a0018 by thread T16 (mutexes: write M562522896233146464):
    #0 nmhandle_free /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1027 (libisc.so.1504+0x3e3b7)
    #1 nmhandle_deactivate /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1057 (libisc.so.1504+0x3e59f)
    #2 isc_nmhandle_unref /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1108 (libisc.so.1504+0x409f0)
    #3 fetch_callback /home/ondrej/Projects/bind9/lib/ns/query.c:5680 (libns.so.1502+0x46b71)
    #4 dispatch /home/ondrej/Projects/bind9/lib/isc/task.c:1134 (libisc.so.1504+0x56f36)
    #5 run /home/ondrej/Projects/bind9/lib/isc/task.c:1319 (libisc.so.1504+0x56f36)
    #6 <null> <null> (libtsan.so.0+0x29b3d)

  Previous atomic write of size 8 at 0x7b90000a0018 by thread T1:
    #0 __tsan_atomic64_fetch_sub <null> (libtsan.so.0+0x648dd)
    #1 isc_nmhandle_unref /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1069 (libisc.so.1504+0x4093c)
    #2 isc__nm_uvreq_put /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1214 (libisc.so.1504+0x41bef)
    #3 udp_send_cb /home/ondrej/Projects/bind9/lib/isc/netmgr/udp.c:439 (libisc.so.1504+0x46c1d)
    #4 <null> <null> (libuv.so.1+0x1d283)
    #5 <null> <null> (libtsan.so.0+0x29b3d)

  Location is heap block of size 7489 at 0x7b90000a0000 allocated by thread T8:
    #0 malloc <null> (libtsan.so.0+0x2b1a3)
    #1 default_memalloc /home/ondrej/Projects/bind9/lib/isc/mem.c:685 (libisc.so.1504+0x33fee)
    #2 mem_get /home/ondrej/Projects/bind9/lib/isc/mem.c:598 (libisc.so.1504+0x34c7e)
    #3 mem_allocateunlocked /home/ondrej/Projects/bind9/lib/isc/mem.c:1222 (libisc.so.1504+0x34c7e)
    #4 isc___mem_allocate /home/ondrej/Projects/bind9/lib/isc/mem.c:1242 (libisc.so.1504+0x34c7e)
    #5 isc__mem_allocate /home/ondrej/Projects/bind9/lib/isc/mem.c:2387 (libisc.so.1504+0x3be64)
    #6 isc___mem_get /home/ondrej/Projects/bind9/lib/isc/mem.c:1007 (libisc.so.1504+0x3c6ca)
    #7 isc__mem_get /home/ondrej/Projects/bind9/lib/isc/mem.c:2365 (libisc.so.1504+0x3aef1)
    #8 alloc_handle /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:916 (libisc.so.1504+0x40547)
    #9 isc__nmhandle_get /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:940 (libisc.so.1504+0x40547)
    #10 udp_recv_cb /home/ondrej/Projects/bind9/lib/isc/netmgr/udp.c:312 (libisc.so.1504+0x46841)
    #11 <null> <null> (libuv.so.1+0x1d6d4)
    #12 <null> <null> (libtsan.so.0+0x29b3d)

  Mutex M562522896233146464 is already destroyed.

  Thread T16 'isc-worker0007' (tid=29211, running) created by main thread at:
    #0 pthread_create <null> (libtsan.so.0+0x2be1b)
    #1 isc_thread_create /home/ondrej/Projects/bind9/lib/isc/pthreads/thread.c:75 (libisc.so.1504+0x7bc54)
    #2 isc_taskmgr_create /home/ondrej/Projects/bind9/lib/isc/task.c:1410 (libisc.so.1504+0x59cf3)
    #3 create_managers main.c:902 (named+0x1aeec)
    #4 setup main.c:1235 (named+0x1aeec)
    #5 main main.c:1515 (named+0x1aeec)

  Thread T1 'isc-net-0000' (tid=29196, running) created by main thread at:
    #0 pthread_create <null> (libtsan.so.0+0x2be1b)
    #1 isc_thread_create /home/ondrej/Projects/bind9/lib/isc/pthreads/thread.c:75 (libisc.so.1504+0x7bc54)
    #2 isc_nm_start /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:149 (libisc.so.1504+0x3ec4a)
    #3 create_managers main.c:895 (named+0x1ae90)
    #4 setup main.c:1235 (named+0x1ae90)
    #5 main main.c:1515 (named+0x1ae90)

  Thread T8 'isc-net-0007' (tid=29203, running) created by main thread at:
    #0 pthread_create <null> (libtsan.so.0+0x2be1b)
    #1 isc_thread_create /home/ondrej/Projects/bind9/lib/isc/pthreads/thread.c:75 (libisc.so.1504+0x7bc54)
    #2 isc_nm_start /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:149 (libisc.so.1504+0x3ec4a)
    #3 create_managers main.c:895 (named+0x1ae90)
    #4 setup main.c:1235 (named+0x1ae90)
    #5 main main.c:1515 (named+0x1ae90)

SUMMARY: ThreadSanitizer: data race /home/ondrej/Projects/bind9/lib/isc/netmgr/netmgr.c:1027 in nmhandle_free