[$] Hardening fixes lead to hard questions

Kees Cook's 'hardening
fixes' pull request for the 6.16 merge window looked like a
straightforward exercise; it only contained four commits. So just about
everybody was surprised when it resulted in Cook being temporarily blocked
from his kernel.org account among fears of malicious activity. When the
dust settled, though, the red alert was canceled. It turns out,
surprisingly, that Git is a tool with which one can inflict substantial
self-harm in a moment of inattention.