On our CI systems, on builders that run on real storage and not RAM disk, we see occasional failures of the IMPORT TABLESPACE tests, because a wait for a log checkpoint is hanging with a stack trace like this:
Actually, the checkpoint there should be unnecessary, but that is not the main point here.
I was able to reproduce this on ext4fs on storage with 4096-byte physical block size using a RelWithDebInfo build. Previous attempts on an NVMe with 512-byte physical block size failed.
The test invocation was:
I think that applying the first commit of MDEV-26827 (to invoke buf_flush_list() from fewer threads) might fix this. That commit is also removing the log_make_checkpoint() call from row_import_cleanup(), but when testing the fix we obviously must retain that call, because our test case cannot fail if that call is not present.