On Wed, Mar 29, 2017 at 11:15 AM, Kees Cook <[email protected]> wrote:
> Based on PaX's x86 pax_{open,close}_kernel() implementation, this
> allows HAVE_ARCH_RARE_WRITE to work on x86.
>
> +
> +static __always_inline unsigned long __arch_rare_write_begin(void)
> +{
> + unsigned long cr0;
> +
> + preempt_disable();
This looks wrong. DEBUG_LOCKS_WARN_ON(!irqs_disabled()) would work,
as would local_irq_disable(). There's no way that just disabling
preemption is enough.
(Also, how does this interact with perf nmis?)
--Andy
