Messages in this thread | | | From | Andy Lutomirski <> | Date | Wed, 29 Mar 2017 15:38:43 -0700 | Subject | Re: [RFC v2][PATCH 04/11] x86: Implement __arch_rare_write_begin/unmap() |
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On Wed, Mar 29, 2017 at 11:15 AM, Kees Cook <keescook@chromium.org> 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
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