Amavis just stops and exits

[Alex]

Hi,

>>> > I have a fedora15 server with amavisd-new-2.6.6-1 and
>>> > spamassassin-3.3.2-7 and occasionally amavisd just exits
>>> > and has to be restarted.
>>
>>> > Apr 20 10:38:33 mail amavis[8442]:
>>> >   logging initialized, log level 2, syslog: amavis.mail
>>> > Apr 20 10:38:33 mail amavis[8442]:
>>> >   Valid PID file (younger than sys uptime 14 6:55:00)
>>
>>> The second event looks loks like a normal restart: the process
>>> 17612 is shutting down, while the new 8442 is starting.
>>> Something is sending a restart signal to amavisd, perhaps
>>> some cron job or a log file rotator.
>>
>> P.S.:
>>
>> if the new starting process (like the 8442 from your log)
>> does not come up but fails during a start, a possible reason
>> is that some files (like a config file or DKIM keys file) is
>> too strongly protected, so a start as root succeeds, but a
>> start with reduced privileges fails.
>
> After your suggestions, I'm really thinking it's due to an unreliable
> "service amavisd reload" on fedora15, and instead amavisd existing and
> not being restarted.

It happened again today, and it looks like there are a few stuck
amavisd processes:

# ps ax|grep amavisd
  944 ?        Ssl  483:00 clamd.amavisd -c /etc/clamd.d/amavisd.conf
--pid /var/run/clamd.amavisd/clamd.pid
10877 ?        S      0:00 smtp -n smtp-amavis -t unix -u -o
smtp_data_done_timeout=1200 -o smtp_send_xforward_command=yes -o
disable_dns_lookups=yes -o max_use=20
11086 pts/0    S+     0:00 grep --color=auto amavisd
25025 ?        S      0:39 amavisd (ch20-finish)
26842 ?        S      0:36 amavisd (ch20-finish)
28176 ?        S      1:58 amavisd (ch20-finish)
28255 ?        S      1:30 amavisd (ch15-finish)

The remaining processes wouldn't exit with just kill, and required
"killall -9 amavisd" to kill them. There were then also these entries
in the logs:

Apr 25 11:58:49 portal amavis[10966]: (10966-01-3) (!)TempDir removal:
tempdir is to be PRESERVED:
/var/spool/amavisd/tmp/amavis-20120425T115816-10966
Apr 25 11:58:49 portal amavis[10017]: (10017-01-23) (!)TempDir
removal: tempdir is to be PRESERVED:
/var/spool/amavisd/tmp/amavis-20120425T115402-10017

What could be the cause of amavisd just going catatonic?

Thanks,
Alex