[PATCH 1/3] x86/panic: Fix re-entrance problem due to panic on NMI

[peterz@xxxxxxxxxxxxx (Peter Zijlstra)]

On Wed, Jul 22, 2015 at 11:14:21AM +0900, Hidehiro Kawai wrote:
> +DEFINE_SPINLOCK(panic_lock);

At the very least this should be a raw spinlock, but wth aren't you
using a simple atomic_xchg() ?