Re: [PATCH 0/8] Fix VMA tree modification under mmap read lock

Vlastimil Babka
2023-03-28T09:11:09Z

On 3/27/23 21:48, Liam R. Howlett wrote:
> * Andrew Morton <akpm@linux-foundation.org> [230327 15:35]:
>> On Mon, 27 Mar 2023 14:55:24 -0400 "Liam R. Howlett" <Liam.Howlett@oracle.com> wrote:
>>
>> > These patches have been in -next since next-20230301, and have received
>> > intensive testing in Android as part of the RCU page fault patchset.
>> > They were also sent as part of the "Per-VMA locks" v4 patch series.
>> > Patches 1 to 7 are bug fixes for RCU mode of the tree and patch 8 enables
>> > RCU mode for the tree.
>>
>> What's happening here? I assume you've decided that the first 8
>> patches of the "Per-VMA locks v4" series should be fast-tracked into
>> 6.3-rcX and backported? And we retain the rest of that series for
>> 6.4-rc1?
>
> Yes, they need to be backported and fast tracked to fix the issue syzbot
> found.

Stable usually wants the "mainline first" which means fast tracking first,
then once it's in mainline, they pick it and annotate with mainline commit id.

One question is how Linus would feel about this now for rc5.

Another question is if we should really deviate in the patch 8/8 backport
just because it's not necessary for stable. Generally they would also prefer
not to deviate, unless there's a strong reason.

>>
>> Patch [3/8] hasn't come through to me, to linux-mm or to linux-kernel.
>
> Should arrive shortly, I received it from one of the ML.
>
>