Keep in mind that in a kernel panic no hardware is assumed to work, so assumptions like "just write to storage!" isn't an assumption you can make, you're in a panic the IO could have been literally pulled out.
So just change that assumption since for these edge cases that is an incorrect assumption.
I really have a hard time understanding how anyone could possibly think that's okay.
It sounds like the kernel's quality is so poor that UB is commonplace and even expected at this point. Pretty scary how many systems are relying on this huge pile of broken C code to hopefully only slightly corrupt itself and your system.
I'm not even sure how useful Rust in the kernel is going to be considering they want it to just ignore errors. You can't even have bounds checking on arrays because invalid accesses might be detected at runtime and cause an error, which is totally insane.