[Samba] What could cause an "unclean shutdown" of process?

[Frederic Fournier]

Hello everyone,

I've been experiencing many problems recently with windows software parsing
large text files stored on a samba share (smb version 3.6.3 on
ubuntu12.04). The software, which are running on windows XP stations, are
crashing quite often.

I notice this in the log.smbd at the time of the crash:
[2012/08/28 17:25:21.980609,  3] smbd/server.c:629(smbd_parent_housekeeping)
  Printcap cache time expired.
[2012/08/28 17:25:21.980679,  3] printing/pcap.c:138(pcap_cache_reload)
  reloading printcap cache
[2012/08/28 17:25:21.980756,  3] printing/pcap.c:189(pcap_cache_reload)
  reload status: ok
*[2012/08/28 17:37:08.715154,  3] smbd/server.c:292(remove_child_pid)*
*  smbd/server.c:292 Unclean shutdown of pid 32526*
*[2012/08/28 17:37:08.715318,  1] smbd/server.c:300(remove_child_pid)*
*  Scheduled cleanup of brl and lock database after unclean shutdown*
*[2012/08/28 17:37:28.722037,  1] smbd/server.c:272(cleanup_timeout_fn)*
*  Cleaning up brl and lock database after unclean shutdown*
[2012/08/28 17:38:22.509303,  3] smbd/server.c:629(smbd_parent_housekeeping)
  Printcap cache time expired.
[2012/08/28 17:38:22.509403,  3] printing/pcap.c:138(pcap_cache_reload)
  reloading printcap cache
[2012/08/28 17:38:22.509499,  3] printing/pcap.c:189(pcap_cache_reload)
  reload status: ok
I don't see anything that catches my eye in the other logs (log.nmbd,
log.<client_name>, log.<client_IP>, log.winbindd). The log.<client_name>
shows a very long list of transactions that stops suddently at the time of
the 'unclean shutdown'.

Do you have any idea what could cause this 'unclean shutdown'? What would
be the best way to further diagnose this problem? I've looked into the
servers' log without noticing anything strange?

Thank you very much for your help,

Frederic