BIND 9.6.1-P1 crashing

[Dario Miculinic]

Hello, all.

I'm administrating 4 DNS servers running CentOS release 5.4 and Red Hat Enterprise Linux Server release 5.2. with BIND 
version 9.6.1-P1. On 3 of them BIND crashed 7 times in last 10 days. There's nothing in log files, but we have core dump 
file. I found this in the core dump:

#0  0x080db986 in ttl_sooner (v1=0x0, v2=0x3385b628) at rbtdb.c:752
752     ttl_sooner(void *v1, void *v2) {
(gdb) where
#0  0x080db986 in ttl_sooner (v1=0x0, v2=0x3385b628) at rbtdb.c:752
#1  0x0819e708 in isc_heap_delete (heap=0xb0f751a8, index=2) at heap.c:218
#2  0x080e039f in free_rdataset (rbtdb=0xb0f70008, mctx=0x86c9e98, rdataset=0x3385b628) at rbtdb.c:1273
#3  0x080e04c3 in clean_stale_headers (rbtdb=0xb0f70008, mctx=0x86c9e98, top=0x7fa67700) at rbtdb.c:1331
#4  0x080e10c4 in decrement_reference (rbtdb=0xb0f70008, node=0x36c159f0, least_serial=0,
     nlock=isc_rwlocktype_read, tlock=isc_rwlocktype_none, pruning=isc_boolean_false) at rbtdb.c:1348
#5  0x080ea711 in detachnode (db=0xb0f70008, targetp=0xb4d1f404) at rbtdb.c:4877
#6  0x080ea9b1 in rdataset_disassociate (rdataset=0xb03f22d8) at rbtdb.c:7173
#7  0x0812e55a in dns_rdataset_disassociate (rdataset=0xb03f22d8) at rdataset.c:101
#8  0x080c7dfa in msgresetnames (msg=0xb03e1b60, first_section=<value optimized out>) at message.c:463
#9  0x080cb3c5 in msgreset (msg=0x0, everything=isc_boolean_false) at message.c:545
#10 0x080cbd05 in dns_message_reset (msg=0xb03e1b60, intent=1) at message.c:800
#11 0x0804dbfc in exit_check (client=0xb03fca70) at client.c:639
#12 0x0806007c in query_find (client=0xb03fca70, event=0x0, qtype=1) at query.c:4914
#13 0x08063490 in query_resume (task=0xad4f6bd0, event=0x98cbdb8) at query.c:3171
#14 0x081b9221 in run (uap=0xb7f2a008) at task.c:862
#15 0x0059645b in pthread_create@@GLIBC_2.1 () from /lib/libpthread.so.0
#16 0x004ee24e in profil_counter () from /lib/libc.so.6


I couldn't get core dump file from Red Hat server, but in every core dump file on CentOS ttl_sooner function is 
mentioned. Does anyone know what this could be and how to fix it?

Thanks in advance.