[Pkg-exim4-users] failed to write to main log: length=164 result=-1 errno=9 (Bad file descriptor)

[list.exim at artfulrobot.uk]

Hi,

I've been using exim4 on debian for years but after a recent upgrade to 
Debian 11 (bullseye) I'm encountering some strange errors.

Background/context:

* I have a CRM system running on the same box as exim. The CRM connects 
over SMTP on localhost:25.

* The CRM submits a message, it is accepted AND DELIVERED by exim, BUT 
it seems exim crashes out at the end, which leads the CRM to think it 
didn't work (so it keep sending - aargh!).

Research / error /debugging/logs

The /var/log/exim4/paniclog shows:

2022-03-16 15:35:05 1nUVg0-00117b-Vp <= 
b.1228.83322.004d859653543c1b at redacted.com H=localhost (redacted.com) 
[127.0.0.1] P=esmtp S=22207
2022-03-16 15:35:05 1nUVg0-00117b-Vp failed to write to main log: 
length=164 result=-1 errno=9 (Bad file descriptor)


Wheres the mainlog just shows a happy world where things got delivered ok:

2022-03-16 15:35:04 1nUVg0-00117b-VV <= 
b.1228.83321.3963f2f5ad0b0d59 at redacted.com H=localhost (redacted.com) 
[127.0.0.1] P=esmtp S=22225
2022-03-16 15:35:05 1nUVg0-00117b-VV => recipient at example.org 
R=dnslookup_relay_to_domains T=remote_smtp H=example.org [1.2.3.4] 
X=TLS1.3:ECDHE_SECP256R1__RSA_PSS_RSAE_SHA256__AES_256_GCM:256 CV
=yes DN="CN=example.org" K C="250- 21795 byte chunk, total 23291\\n250 
OK id=1nUVg1-000jUL-IA"
2022-03-16 15:35:05 1nUVg0-00117b-VV Completed
... other successful log stuff appears here; it's not that the disk is 
full or exim can't write to mainlog...


And, as I said above, the mail IS delivered just fine.


I was able to add some debugging at the CRM client end, and basically 
exim seems to error after the . line is sent at the end of the body:


...body of message, ending with...
--=_07398c9e69f94bbbd6e8d2855ee8e997--
2022-03-16 16:35:04 Send: .
2022-03-16 16:35:05 Recv: 421 redacted.com Unexpected failure, please 
try later - closing connection.
2022-03-16 16:35:05 Send: RSET
2022-03-16 16:35:05 Send: QUIT
2022-03-16 16:35:05 send error: unknown error
2022-03-16 16:35:05 Send: QUIT



Any help would be gratefully received.

Thanks,

Rich