[PATCH] maple_tree: Fix mas_next() when already on the last node entry

[Andrew Morton]

On Tue, 17 May 2022 17:34:58 +0200 Sven Schnelle <svens at linux.ibm.com> wrote:

> Liam Howlett <liam.howlett at oracle.com> writes:
> 
> > It is possible to return the metadata as the next entry if the last node
> > entry is already in the maple state and the limit is not reached.  Check
> > for this condition in mas_next_nentry() where the node end is returned.
> >
> > Signed-off-by: Liam R. Howlett <Liam.Howlett at oracle.com>
> 
> Thanks, that matches my observation from the initial report that we're
> returing metadata. I just applied the patch to next-20220516 and i'm no
> longer able to trigger the crash. So feel free to add my:
> 
> Tested-by: Sven Schnelle <svens at linux.ibm.com>

Thanks.

> However, as Heiko already wrote in another mail i would also like to
> request that the maple tree code isn't merged with the next merge
> window. These patches touch a lot of critical infrastructure, and i would like
> to have it in next for at least one development cycle, so we can be sure
> that we've seen and fixed most of the issues.

Agree, it isn't looking good.  If Linus does an -rc8 (unlikely) then
perhaps we'll be in better shape.