sendmail, spamass-milter and zombies

[Stephen Borrill <netbsd%precedence.co.uk@localhost>]

I'm using sendmail and spamass-milter from pkgsrc on netbsd-5. When I use 
the -B flag to spamass-milter to forward on spam mail to another address, 
when a mail gets forwarded the child sendmail process (often) remains as a 
zombie.

So:
1# ps ax | grep 'ZW.*sendmail'
 2062 ?      ZW   0:00.00 (sendmail)
14832 ?      ZW   0:00.00 (sendmail)
16310 ?      ZW   0:00.00 (sendmail)
18324 ?      ZW   0:00.00 (sendmail)
18553 ?      ZW   0:00.00 (sendmail)
19206 ?      ZW   0:00.00 (sendmail)
19962 ?      ZW   0:00.00 (sendmail)
26535 ?      ZW   0:00.00 (sendmail)
28491 ?      ZW   0:00.00 (sendmail)

2# grep sendmail.28491 /var/log/maillog
Jan 20 11:00:20 netmanager sendmail[28491]: s0KB0K3A028491: from=root, size=10340, 
class=0, nrcpts=1, msgid=<201401201100.s0G7LIpp019527%u-works.kr@localhost>, 
relay=root@localhost
Jan 20 11:00:20 netmanager sendmail[28491]: STARTTLS=client, relay=[127.0.0.1], 
version=TLSv1/SSLv3, verify=FAIL, cipher=DHE-RSA-AES256-GCM-SHA384, bits=256/256
Jan 20 11:00:21 netmanager sendmail[28491]: s0KB0K3A028491: 
to=spam%XXXXXXX.co.uk@localhost, ctladdr=root (0/0), delay=00:00:01, 
xdelay=00:00:01, mailer=relay, pri=40340, relay=[127.0.0.1] [127.0.0.1], 
dsn=2.0.0, stat=Sent (s0KB0K9D023167 Message accepted for delivery)

Restarting spamass-milter gets rid of the zombies. An example spamassassin 
run:

Jan 20 13:00:24 netmanager sm-mta[15604]: s0KD0LLF015604: milter=spamassassin, 
action=rcpt, continue
Jan 20 13:00:25 netmanager sm-mta[15604]: s0KD0LLF015604: from=<>, size=16566, 
class=0, nrcpts=1, msgid=<201401201300.s0IA20am014151%u-works.kr@localhost>, 
proto=ESMTP, daemon=MTA, relay=u-works.kr [115.68.53.98]
Jan 20 13:00:25 netmanager sm-mta[15604]: s0KD0LLF015604: milter=spamassassin, 
action=header, continue
Jan 20 13:00:25 netmanager sm-mta[15604]: s0KD0LLF015604: milter=spamassassin, 
action=eoh, continue
Jan 20 13:00:25 netmanager sm-mta[15604]: s0KD0LLF015604: milter=spamassassin, 
action=body, continue
Jan 20 13:00:28 netmanager sm-mta[15604]: s0KD0LLF015604: Milter add: header: 
X-Spam-Flag: YES
Jan 20 13:00:28 netmanager sm-mta[15604]: s0KD0LLF015604: Milter add: header: 
X-Spam-Status: Yes, score=17.5 required=1.0 
tests=ADVANCE_FEE_2_NEW_MONEY,\n\tADVANCE_FEE_3_NEW,ADVANCE_FEE_3_NEW_MONEY,ADVANCE_FEE_4_NEW,\n\tADVANCE_FEE_4_NEW_MONEY,ADVANCE_FEE_5_NEW,ADVANCE_FEE_5_NEW_MONEY,BAYES_99,\n\tDEAR_BENEFICIARY,FORM_FRAUD_3,FORM_FRAUD_5,HK_SCAM_N2,HTML_MESSAGE,\n\tLOTS_OF_MONEY,MONEY_ATM_CARD,MONEY_FRAUD_3,MONEY_FRAUD_5,MONEY_FRAUD_8,\n\tT_FILL_THIS_FORM_SHORT,T_TVD_MIME_NO_HEADERS
 autolearn=spam version=3.3.2
Jan 20 13:00:28 netmanager sm-mta[15604]: s0KD0LLF015604: milter=spamassassin, 
reject=550 5.7.1 Blocked by SpamAssassin
Jan 20 13:00:28 netmanager sm-mta[15604]: s0KD0LLF015604: Milter: data, 
reject=550 5.7.1 Blocked by SpamAssassin
Jan 20 13:00:28 netmanager sm-mta[15604]: s0KD0LLF015604: 
to=<fax%XXXXXXXX.co.uk@localhost>, delay=00:00:04, pri=46566, stat=Blocked by 
SpamAssassin

I can't see any obvious reason why this is happening.

--
Stephen