Hi Emmanuel,
Can you please share the kernel config where the problem is reproducible, along with the full dmesg?
I think "test_meminit: failures: 70 out of 130" is a red herring, the kernel probably does not enable memory initialization, that's why the tests are failing.
We could see that from the "mem auto-init" line in the dmesg, but it got stripped away.
The leaked reference probably belongs to lib/test_ref_tracker.c, which is a completely different test suite.
