for the MPTCP upstream project, we are running syzkaller [1] continuously to qualify our kernel changes.

We found one issue with kmemleak and its handling of kfree_rcu.

Specifically, it looks like kmemleak falsely reports memory-leaks when the object is being freed by kfree_rcu after a certain grace-period.

For example, https://github.com/multipath-tcp/mptcp_net-next/issues/398#issuecomment-1584819482 shows how the syzkaller program reliably produces a kmemleak report, although the object is not leaked (we confirmed that by simply increasing MSECS_MIN_AGE to something larger than the grace-period).

Is this a known limitation of kmemleak, or is there something else that needs to be done ?

Thanks,

Christoph

[1] https://github.com/google/syzkaller