[Samba] samba on ubuntu 22 lts breaks after unattended-upgrade

[Jakob Curdes]

Hello, this morning we had the unpleasant experience of two DCs breaking 
at the same time, no logins, no DNS resolution, any call to samba 
binaries fails with an error message similar to :

libldbsamba.so.0 : ldb_msg_element_is_inaccessible
(cannot copy&paste as I disabled network access to this server).

We first thought we had a crashed AD structure. Reverting to a copy one 
of the DCs from 06:00 this morning worked, alls services available, then 
after 30 mins again similar problems (but logins continued to work this 
time). After a lot of trial and failure we could conclude that the error 
happened some time this morning, but as soon as I activate an older copy 
of the server, after some time the same symptoms appear. I then started 
to look at updates, and found that the server had applied 
unattended-upgrades this morning. After applying these updates, the 
samba binaries break. It seems to be a security update (see 
https://bugs.launchpad.net/ubuntu/jammy/+source/samba/+bug/2014052). I 
could not find any further descriptions for this error, so it seems to 
be a specific case. We had used the van Belle repos, then after the got 
"stalled" we switched to the classical U22 samba, maybe there is a 
reason to find?

Samba version is 4.15.13-Ubuntu.

I now disabled unattended-upgrades and the DC is up and running since 2 
hours, which was never achieved since this morning.

Does this ring a bell with anybody? My current recovery plan is to setup 
a new "DC3" with U22 and join it to the domain, then demote the old "DC1".

Best regards, JC