asterisk users - Oct 2006 - Core dumps when Releasing clone lock

Hi,

Our Asterisk server has started core dumping more often, which seems to 
be related to when it releases the clone lock, and it stops masquerading 
the channel.
So, I wondered if anyone had an idea what causes these masquerading 
attempts.

Our system is running: Asterisk SVN-branch-1.2-r31555M.

Full-log:
Oct 20 11:09:37 DEBUG[57839] chan_sip.c: Assigning Replace-Call-ID Info 
3c61d85c30d4-dg23pmqot0uj@snom360 to REPLACE_CALL_ID
Oct 20 11:09:37 DEBUG[57839] chan_sip.c: 202 Accepted (supervised)
Oct 20 11:09:37 VERBOSE[57839] logger.c:     -- Stopped music on hold on 
IAX2/provider-15
Oct 20 11:09:37 DEBUG[57839] channel.c: Scheduling timer at 0 sample 
intervals
Oct 20 11:09:37 DEBUG[57839] channel.c: Planning to masquerade channel 
IAX2/provider-15 into the structure of SIP/XXXXXX-158e
Oct 20 11:09:37 DEBUG[57839] channel.c: Done planning to masquerade 
channel IAX2/provider-15 into the structure of SIP/XXXXXX-158e
Oct 20 11:09:37 DEBUG[57839] channel.c: Got clone lock for masquerade on 
'IAX2/provider-15' at 0x94334cc
Oct 20 11:09:37 DEBUG[57839] chan_sip.c: update_call_counter(XXXXXX) - 
decrement call limit counter
Oct 20 11:09:37 DEBUG[57839] channel.c: Putting channel IAX2/provider-15 
in 256/256 formats
Oct 20 11:09:37 DEBUG[57839] channel.c: Released clone lock on 
'SIP/XXXXXX-158e<ZOMBIE>'
Oct 20 11:09:37 DEBUG[57839] channel.c: Done Masquerading 
IAX2/provider-15 (6)
Oct 20 11:09:37 DEBUG[57839] channel.c: Didn't get a frame from channel: 
SIP/XXXXXX-158e<ZOMBIE>
Oct 20 11:09:37 DEBUG[57839] channel.c: Bridge stops bridging channels 
SIP/XXXXXX-c3c3 and SIP/XXXXXX-158e<ZOMBIE>
Oct 20 11:09:37 DEBUG[57839] app_dial.c: Exiting with DIALSTATUS=ANSWER.
Asterisk exited on signal 11.

GDB:
#0  0x282e1373 in pthread_testcancel () from /usr/lib/libpthread.so.1
#1  0x282d992e in pthread_mutexattr_init () from /usr/lib/libpthread.so.1
#2  0x28145450 in ?? ()


Regards
?yvind Albrigtsen