[$] Hardening fixes lead to hard questions

Kees Cook's "hardeningfixes" pull request for the 6.16 merge window looked like astraightforward exercise; it only contained four commits. So just abouteverybody was surprised when it resulted in Cook being temporarily blockedfrom his kernel.org account among fears of malicious activity. When thedust settled, though, the red alert was canceled. It turns out,surprisingly, that Git is a tool with which one can inflict substantialself-harm in a moment of inattention.