[PATCH v9 0/6] Optionally randomize kernel stack offset each syscall

Thomas Gleixner tglx at linutronix.de
Thu Apr 1 14:33:02 BST 2021


On Thu, Apr 01 2021 at 09:37, Will Deacon wrote:
> On Wed, Mar 31, 2021 at 01:54:52PM -0700, Kees Cook wrote:
>> Hi Will (and Mark and Catalin),
>> 
>> Can you take this via the arm64 tree for v5.13 please? Thomas has added
>> his Reviewed-by, so it only leaves arm64's. :)
>
> Sorry, these got mixed up in my inbox so I just replied to v7 and v8 and
> then noticed v9. Argh!
>
> However, I think the comments still apply: namely that the dummy "=m" looks
> dangerous to me

> https://lore.kernel.org/r/20210401083034.GA8554@willie-the-truck

Hrmpf, didn't think about that.

> and I think you're accessing pcpu variables with preemption enabled
> for the arm64 part:

That's my fault. On x86 this is invoked right after coming up into C
code and _before_ enabling interrupts, which I why I suggested not to
use the wrapped one. raw_cpu_read() should be fine everywhere.

Thanks,

        tglx



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