data race with stats channel on main

Job #1162539 failed for d5aac19e:

core available

==14330==ERROR: AddressSanitizer: unknown-crash on address 0x7f8a499cd610 at pc 0x7f8a5955b314 bp 0x7f8a4ab102a0 sp 0x7f8a4ab10298
READ of size 2 at 0x7f8a499cd610 thread T11
    #0 0x7f8a5955b313 in isc__nmsocket_init netmgr/netmgr.c:959
    #1 0x7f8a59569eb1 in isc__nm_async_tcpchildaccept netmgr/tcp.c:444
    #2 0x7f8a595608d4 in process_queue netmgr/netmgr.c:628
    #3 0x7f8a5956187f in async_cb netmgr/netmgr.c:596
    #4 0x7f8a56bcd667  (/usr/lib/x86_64-linux-gnu/libuv.so.1+0x10667)
    #5 0x7f8a56bdc4af in uv__io_poll (/usr/lib/x86_64-linux-gnu/libuv.so.1+0x1f4af)
    #6 0x7f8a56bcdf84 in uv_run (/usr/lib/x86_64-linux-gnu/libuv.so.1+0x10f84)
    #7 0x7f8a59560a59 in nm_thread netmgr/netmgr.c:500
    #8 0x7f8a56b99fa2 in start_thread /build/glibc-vjB4T1/glibc-2.28/nptl/pthread_create.c:486
    #9 0x7f8a55bb34ce in clone (/lib/x86_64-linux-gnu/libc.so.6+0xf94ce)

Address 0x7f8a499cd610 is located in stack of thread T13
SUMMARY: AddressSanitizer: unknown-crash netmgr/netmgr.c:959 in isc__nmsocket_init
Shadow bytes around the buggy address:
  0x0ff1c9331a70: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331a80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331a90: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331aa0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331ab0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
=>0x0ff1c9331ac0: 00 00[00]00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331ad0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331ae0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331af0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331b00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0ff1c9331b10: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
Shadow byte legend (one shadow byte represents 8 application bytes):
  Addressable:           00
  Partially addressable: 01 02 03 04 05 06 07
  Heap left redzone:       fa
  Freed heap region:       fd
  Stack left redzone:      f1
  Stack mid redzone:       f2
  Stack right redzone:     f3
  Stack after return:      f5
  Stack use after scope:   f8
  Global redzone:          f9
  Global init order:       f6
  Poisoned by user:        f7
  Container overflow:      fc
  Array cookie:            ac
  Intra object redzone:    bb
  ASan internal:           fe
  Left alloca redzone:     ca
  Right alloca redzone:    cb
Thread T11 created by T0 here:
    #0 0x7f8a599a1db0 in __interceptor_pthread_create (/usr/lib/x86_64-linux-gnu/libasan.so.5+0x50db0)
    #1 0x7f8a59696c5a in isc_thread_create pthreads/thread.c:73
    #2 0x7f8a59552176 in isc_nm_start netmgr/netmgr.c:223
    #3 0x557769fe5333 in create_managers /builds/isc-projects/bind9/bin/named/main.c:909
    #4 0x557769fe5333 in setup /builds/isc-projects/bind9/bin/named/main.c:1223
    #5 0x557769fe5333 in main /builds/isc-projects/bind9/bin/named/main.c:1523
    #6 0x7f8a55ade09a in __libc_start_main ../csu/libc-start.c:308

==14330==ABORTING