Re: [PATCH v3] lib/maple_tree: fix swapped arguments in mas_safe_pivot() call

[Liam R. Howlett]

* Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> [260326 14:44]:
> On Thu, 26 Mar 2026 19:02:35 +0100 "Vlastimil Babka (SUSE)" <vbabka@xxxxxxxxxx> wrote:
> 
> > 
> > I'm not a maple tree expert but this looks obviously correct enough. So I
> > won't speculate on the impact of this bug, but:
> > 
> > Acked-by: Vlastimil Babka (SUSE) <vbabka@xxxxxxxxxx>
> > 
> > I guess since it's old and not in mm-hotfixes, we can afford to wait for
> > Liam who should be back before the merge window.
> 
> Yup, I'm keeping this parked until Liam is back on deck.
> 
> > I'm not sure how to
> > handle the fact that this patch has been withdrawn [1] however.
> > 
> > [1] https://lore.kernel.org/all/E1A667AB-DCE4-4034-A36B-DAA458780A81@xxxxxxxxxxxxx/
> 
> Waiting to see what Liam says.  If he likes it then let's proceed.

This fix looks correct, but I'm not okay with taking it for the
following reasons:

1. It does not have a reproducer to catch this bug showing up again.
Although unlikely to show up again, it certainly won't with a
reproducer.  I have a strict policy of requiring a test case for each
fix that should either go into the testing module or the test framework.

Every regression or bug has a reproducer as the next patch after a bug
fix.  This allows for successful running of the test cases without
failure (git bisect still works), while maintaining less overhead for
backports.

2. The reason given why this hasn't been triggered does not seem
correct.  If you create the test case, then you would know why it wasn't
triggered instead of assuming what you stated.

Maybe I've messed something bigger up and that code isn't reachable.  No
one knows why it hasn't showed up because proper care hasn't been taken
in analyzing why it hasn't showed up.

It also means instead of knowing what's going on, you're making more
work for stable.

This is just sloppy.

To put it another way: what are the user-visible runtime effects of this
change?

3. The SoB email address; I'm objecting.

I'm not entirely sure what's been done about these Josh Law patches.  It
seems some sort of bot is involved without proper oversight.

If these problems are not addressed, I will rewrite the patch with a
reproducer along with a note pointing to these interactions as credit to
where the bug was reported - since I have no idea WHO reported it.

Thanks,
Liam