Data directory of mysqld.1 at the assertion, 2026-10-16:
  mariadbd: /data/Server/13.1/storage/innobase/log/log0log.cc:1590: void log_t::persist(lsn_t): Assertion `is_mmap_writeable()' failed.

Build: /data/Server_bin/13.1_debug_Og (13.1.2-MariaDB-debug, source revision
5ab51d6248bb6dc2c5a8c3d3cd7a8d2d721224d8), sources /data/Server/13.1.

Taken with the unchanged test (test.test here = mariadb-test/main/test.test):
  cd /data/Server_bin/13.1_debug_Og/mariadb-test
  backup_on_restart=1 ./mtr test
mysqltest reads $backup_on_restart from the environment, so include/restart_mysqld.inc tars the
vardir to /tmp/mtr-backup.tgz between the shutdown that asserts and the restart. data/ and
mysqld.1.err were extracted from that tarball; the tarball was then deleted.
MTR's own copy (var/log/main.test/mysqld.1/data) is taken after the restart, the DROP TABLE and the
final shutdown, so it is not this state.

  data/          datadir at the assertion; data/core is the core of that crash
  mysqld.1.err   error log up to the assertion; line 98 is the command line of the server that
                 asserts (--innodb-log-archive=ON --innodb-log-recovery-target=56820), line 198 the assertion
  test.test      the test

Replay (verified: same assertion on shutdown, exit status 134):
  cp -a data <copy> && rm <copy>/core
  /data/Server_bin/13.1_debug_Og/bin/mariadbd --no-defaults --datadir=<copy> --socket=<sock> --skip-networking \
    --innodb-log-archive=ON --innodb-log-recovery-target=56820 &
  /data/Server_bin/13.1_debug_Og/bin/mariadb --no-defaults -uroot -S <sock> -e SHUTDOWN
