Re: 1808d65b55 ("asm-generic/tlb: Remove arch_tlb*_mmu()"): BUG: KASAN: stack-out-of-bounds in __change_page_attr_set_clr

Nadav Amit
2019-04-12T19:42:37Z

> On Apr 12, 2019, at 11:19 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Fri, Apr 12, 2019 at 03:11:22PM +0000, Nadav Amit wrote:
>>> On Apr 12, 2019, at 4:17 AM, Peter Zijlstra <peterz@infradead.org> wrote:
>
>>> To clarify, 'that' is Nadav's patch:
>>>
>>> 515ab7c41306 ("x86/mm: Align TLB invalidation info")
>>>
>>> which turns out to be the real problem.
>>
>> Sorry for that. I still think it should be aligned, especially with all the
>> effort the Intel puts around to avoid bus-locking on unaligned atomic
>> operations.
>
> No atomics anywhere in sight, so that's not a concern.

You are right. I still think that at least TLB-wise it should be better to
have the argument off-stack. I’ll try to run some experiments, based on
your feedback, and send a patch on top of your revert.

Sorry for the mess, again.