TSAN data race in zone.c

TSAN reports a race between dns_zone_rekey() and zone_maintenance(). Turns out zone_maintenance() accesses all the timer info unlocked, whoops.

WARNING: ThreadSanitizer: data race 
  Write of size 8 at 0x000000000001 by main thread (mutexes: write M1):
    #0 dns_zone_rekey lib/dns/zone.c:22097
    #1 named_server_dnssec bin/named/server.c:15335
    #2 named_control_docommand bin/named/control.c:206
    #3 control_command bin/named/controlconf.c:390
    #4 task_run lib/isc/task.c:470
    #5 task__run lib/isc/task.c:287
    #6 isc__job_cb lib/isc/job.c:75
    #7 uv__run_idle /usr/src/libuv-v1.44.1/src/unix/loop-watcher.c:68
    #8 isc_loopmgr_run lib/isc/loop.c:469
    #9 main bin/named/main.c:1545

  Previous read of size 4 at 0x000000000001 by thread T1:
    #0 isc_time_isepoch lib/isc/time.c:81
    #1 zone_maintenance lib/dns/zone.c:11559
    #2 zone_timer lib/dns/zone.c:15214
    #3 timer_cb lib/isc/timer.c:113
    #4 uv__run_timers /usr/src/libuv-v1.44.1/src/timer.c:178
    #5 isc__trampoline_run lib/isc/trampoline.c:198

  Location is heap block of size 3216 at 0x000000000018 allocated by main thread:
    #0 malloc <null>
    #1 mallocx lib/isc/jemalloc_shim.h:57
    #2 mem_get lib/isc/mem.c:343
    #3 isc__mem_get lib/isc/mem.c:774
    #4 dns_zone_create lib/dns/zone.c:1158
    #5 dns_zonemgr_createzone lib/dns/zone.c:19035
    #6 configure_zone bin/named/server.c:6791
    #7 configure_view bin/named/server.c:4208
    #8 load_configuration bin/named/server.c:9271
    #9 run_server bin/named/server.c:10065
    #10 task_run lib/isc/task.c:470
    #11 task__run lib/isc/task.c:287
    #12 isc__job_cb lib/isc/job.c:75
    #13 uv__run_idle /usr/src/libuv-v1.44.1/src/unix/loop-watcher.c:68
    #14 isc_loopmgr_run lib/isc/loop.c:469
    #15 main bin/named/main.c:1545

  Mutex M1 (0x000000000028) created at:
    #0 pthread_mutex_init <null>
    #1 dns_zone_create lib/dns/zone.c:1163
    #2 dns_zonemgr_createzone lib/dns/zone.c:19035
    #3 configure_zone bin/named/server.c:6791
    #4 configure_view bin/named/server.c:4208
    #5 load_configuration bin/named/server.c:9271
    #6 run_server bin/named/server.c:10065
    #7 task_run lib/isc/task.c:470
    #8 task__run lib/isc/task.c:287
    #9 isc__job_cb lib/isc/job.c:75
    #10 uv__run_idle /usr/src/libuv-v1.44.1/src/unix/loop-watcher.c:68
    #11 isc_loopmgr_run lib/isc/loop.c:469
    #12 main bin/named/main.c:1545

  Thread T1 'isc-loop-0001' (running) created by main thread at:
    #0 pthread_create <null>
    #1 isc_thread_create lib/isc/thread.c:70
    #2 isc_loopmgr_run lib/isc/loop.c:463
    #3 main bin/named/main.c:1545

SUMMARY: ThreadSanitizer: data race lib/dns/zone.c:22097 in dns_zone_rekey