crash at shutdown in rbtdb.c
Dunno if this is related to #84 (closed) and/or my patch !71 (merged)
2018-03-16.11:33:05.661 general: critical: rbtdb.c:1300: INSIST((((rbtdb->rdatasets[i]).head == ((void *)0)) ? isc_boolean_true : isc_boolean_false)) failed
2018-03-16.11:33:05.675 general: critical: exiting (due to assertion failure)
(gdb) bt
#0 0x00007ff885a46067 in __GI_raise (sig=sig@entry=6) at ../nptl/sysdeps/unix/sysv/linux/raise.c:56
#1 0x00007ff885a47448 in __GI_abort () at abort.c:89
#2 0x000055cefcca24c9 in assertion_failed (file=0x55cefcf1e8aa "rbtdb.c", line=1300, type=4246502448,
cond=0x55cefcf1c7b0 "(((rbtdb->rdatasets[i]).head == ((void *)0)) ? isc_boolean_true : isc_boolean_false)") at ./main.c:248
#3 0x000055cefce98a7a in isc_assertion_failed (file=<optimized out>, line=<optimized out>, type=<optimized out>, cond=<optimized out>) at assertions.c:49
#4 0x000055cefcd802c1 in free_rbtdb (rbtdb=0x7ff87c98d010, log=(unknown: 16), event=0x0) at rbtdb.c:1300
#5 0x000055cefcd832a6 in maybe_free_rbtdb (rbtdb=0x7ff87c98d010) at rbtdb.c:1416
#6 0x000055cefcd833b5 in detach (dbp=0x7ff87c989090) at rbtdb.c:1431
#7 0x000055cefcd22470 in dns_db_detach (dbp=dbp@entry=0x7ff87c989090) at db.c:164
#8 0x000055cefcd188d7 in cache_free (cache=0x7ff87c989010) at cache.c:385
#9 0x000055cefcd19eac in dns_cache_detach (cachep=<optimized out>) at cache.c:476
#10 0x000055cefce358d2 in destroy (view=0x7ff8781fcbf0) at view.c:413
#11 0x000055cefce36ab2 in dns_view_weakdetach (viewp=viewp@entry=0x7ff8788671e8) at view.c:689
#12 0x000055cefce40639 in zone_free (zone=zone@entry=0x7ff878866890) at zone.c:1144
#13 0x000055cefce5c728 in zone_shutdown (task=<optimized out>, event=<optimized out>) at zone.c:12845
#14 0x000055cefcebf237 in dispatch (manager=0x7ff887623010) at task.c:1138
#15 run (uap=0x7ff887623010) at task.c:1310
#16 0x00007ff88612b064 in start_thread (arg=0x7ff8844b4700) at pthread_create.c:309
#17 0x00007ff885af962d in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:111