I searched lore.kernel.org and couldn't find any postings that propose using this in the kernel. I'd encourage you to share a proposal, otherwise the "kernel team" will never be interested, because they'll never hear of it.
That's cool, but it'd be nice to also have a distinction between a get and a copy (like ObjC) or borrow/move (like Rust) to avoid redundant increments and decrements.
Hey, I wrote this GCC plugin to automate reference counting in C. Any bug reports welcome.