- Initialize KASAN before executing SYSINITs.
- Add a kernel config.
- Increase the kernel stack size if KASAN is enabled. Some of the
ASAN instrumentation increases stack usage and it's enough to
trigger stack overflows in ZFS.
- Mark the trapframe as valid in interrupt handlers if it is
assigned to td_intr_frame. Otherwise, an interrupt in a function
which creates a poisoned alloca region can trigger false positives.