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

Andrew Morton akpm at linux-foundation.org
Thu Sep 21 11:25:21 PDT 2023


On Thu, 21 Sep 2023 14:12:34 -0400 "Liam R. Howlett" <Liam.Howlett at oracle.com> 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 at vger.kernel.org, although stable at kernel.org works just fine.



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