Re: [RFC] call_with_creds()

[Al Viro]

On Wed, Jul 18, 2018 at 01:43:00PM -0700, Linus Torvalds wrote:

> What I really think I'd prefer is to have some simple way to "poison"
> current_cred().  It could be something as simple as a per-thread
> counter, and we'd have current_cred() do
> 
>         WARN_ON_ONCE(in_interrupt() || current->cred_poison);

Why is counter any better than LSB of a pointer?