I was able to get a stack trace and reported this upsteam at https://jira.mariadb.org/browse/MDEV-21010
- Bug#943962: mariadb-server-10.3: mysqld crashes and h... Richard van den Berg
- Bug#943962: [debian-mysql] Bug#943962: mariadb-s... Otto Kekäläinen
- Bug#943962: [debian-mysql] Bug#943962: maria... Richard van den Berg
- Bug#943962: [debian-mysql] Bug#943962: m... Otto Kekäläinen
- Bug#943962: [debian-mysql] Bug#94396... Richard van den Berg
- Bug#943962: [debian-mysql] Bug#... Richard van den Berg
- Bug#943962: mariadb-server-10.3: mysqld crashes ... Richard van den Berg
- Bug#943962: Upstream report Richard van den Berg
