RE: [PATCH v4] x86/mce: Avoid infinite loop for copy from user recovery

[Luck, Tony]

> Yah, some printk sprinkling might be a good start. But debugging in that
> atomic context is always nasty. ;-\

Some very light printk sprinkling (one message in queue_task_work() in atomic
context, one each in kill_me_now() and kill_me_maybe() to check when task_work
actually called them.

Cases 1 & 2 (user & normal copyin) now work just fine (hundreds of iterations).

Case 3 (my futex test) just hangs with only two characters making it to the serial port "[ "

Deeply strange.

-Tony