The kernel has very small stacks, and Box::try_new(T {}) does not reliably avoid putting T {} on the stack. It seems the only reasonable way to guarantee that T does not make a trip through the stack is to use unsafe code, with Box::try_new_zeroed() or similar. This requires the new_uninit feature.

I'd love to hear any better ideas of how to handle this... try_new_zeroed only really works safely for types where the zero bit pattern is valid, which doesn't cover all cases that Box::try_new(T {}); does.