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

Liam R. Howlett
2023-03-28T13:03:38Z

* Vlastimil Babka <vbabka@suse.cz> [230328 05:11]:
> 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.

Right. I meant these patches won't cleanly apply to 6.1/6.2 and will
need more than just a cherry-pick due to the vma iterator changes. I
have those modified patches ready to go as well.

>
> 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.

Just to clarify, the change is to remove something that isn't necessary
at all.

>
> >>
> >> 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.
> >
> >
>
>
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