Several buildfarm animals fail tests because of shared memory error

Hello hackers,

I'd like to bring your attention to multiple buildfarm failures, which
occurred this month, on master only, caused by "could not open shared
memory segment ...: No such file or directory" errors.

First such errors were produced on 2024-12-16 by:
leafhopper
Amazon Linux 2023 | gcc 11.4.1 | aarch64/graviton4/r8g.2xl | tharar [ a t ] amazon.com
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=leafhopper&dt=2024-12-16%2012%3A27%3A01
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=leafhopper&dt=2024-12-16%2020%3A40%3A09

and batta:
sid | gcc recent | aarch64 | michael [ a t ] paquier.xyz
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=batta&dt=2024-12-16%2008%3A05%3A04

Then there was alligator:
Ubuntu 24.04 LTS | gcc experimental (nightly build) | x86_64 | tharakan [ a t ] gmail.com
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=alligator&dt=2024-12-19%2001%3A30%3A57

and parula:
Amazon Linux 2 | gcc 13.2.0 | aarch64/Graviton3/c7g.2xl | tharar [ a t ] amazon.com
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=parula&dt=2024-12-21%2009%3A56%3A28

Maybe it's a configuration issue (all animals except batta are owned by
Robins), as described here:
https://www.postgresql.org/docs/devel/kernel-resources.html#SYSTEMD-REMOVEIPC

And maybe leafhopper is faulty by itself, because it also produced very
weird test outputs (in older branches) like:
https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=leafhopper&dt=2024-12-16%2023%3A43%3A03
REL_15_STABLE
-               Rows Removed by Filter: 9990
+               Rows Removed by Filter: 447009543

https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=leafhopper&dt=2024-12-21%2022%3A18%3A04
REL_16_STABLE
-               Rows Removed by Filter: 9990
+               Rows Removed by Filter: 9395

But still why master only?

Unfortunately I'm unable to reproduce such failures locally, so I'm sorry
for such raw information, but I see no way to investigate this further
without assistance. Perhaps owners of these animals could shed some light
on this...

Best regards,
Alexander