Re: [PATCH v2 0/5] mm/mprotect: avoid unnecessary TLB flushes

Dave Hansen
2021-10-26T16:12:40Z

On 10/22/21 2:58 PM, Nadav Amit wrote:
>> [1/5] appears to be a significant fix which should probably be
>> backported into -stable kernels. If you agree with this then I suggest
>> it be prepared as a standalone patch, separate from the other four
>> patches. With a cc:stable.
>
> There is no functionality bug in the kernel. The Knights Landing bug
> was circumvented eventually by changing the swap entry structure so
> the access/dirty bits would not overlap with the swap entry data.

Yeah, it was a significant issue, but we fixed it in here:

> commit 00839ee3b299303c6a5e26a0a2485427a3afcbbf
> Author: Dave Hansen <dave.hansen@linux.intel.com>
> Date: Thu Jul 7 17:19:11 2016 -0700
>
> x86/mm: Move swap offset/type up in PTE to work around erratum