Re: [PATCH 0/2] maple_tree: Fix mas_prev() state regression.

[Andrew Morton]

On Thu, 21 Sep 2023 14:12:34 -0400 "Liam R. Howlett" <Liam.Howlett@xxxxxxxxxx> wrote:

> Pedro Falcato contacted me on IRC with an mprotect regression which was
> bisected back to the iterator changes for maple tree.  Root cause
> analysis showed the mas_prev() running off the end of the VMA space
> (previous from 0) followed by mas_find(), would skip the first value.
> 
> This patch set introduces maple state underflow/overflow so the sequence
> of calls on the maple state will return what the user expects.

It isn't clear what are the user-visible effects of this flaw?  Please
send this along and I'll paste it in.

Patch 1 should be titled "Add mas_is_active ...".

And patch 1 should have had cc:stable in the changelog.

It's stable@xxxxxxxxxxxxxxx, although stable@xxxxxxxxxx works just fine.