I have a 3rd-party module, that throws this whinge:

[   65.831296] INFO: trying to register non-static key.
[   65.831301] the code is fine but needs lockdep annotation.
[   65.831303] turning off the locking correctness validator.

I've identified that it's a call to down(*foo) where foo points to a kmalloc'ed
block of memory that's memset() to all-zeros. What's the initializer/annotation
I need to add to my code?