While updating the official Debian packaging and working on release 10.4.12 I noticed that the mtr testsuite in the s390x build on Launchpad failed on all tests, indicating that mysqld completely crashes.
This was working before, so I did many builds and managed to narrow it down to a SSL/GnuTLS issue.
Build with external libssl-dev passes and tests run OK:
However after activating the source embedded GnuTLS the mysqld starts to crash on all tests:
The change between those builds was:
Switching to OpenSSL in official Debian is not an option due to licensing views. MariaDB has been with GnuTLS and fully working in latest 10.3.22, 10.1, 10.0 etc in Debian.
This is now a regression in 10.4 series. Please help me figure out what it is.