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From: Andrew Morton <akpm@linux-foundation.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>,
	maple-tree@lists.infradead.org, linux-mm@kvack.org,
	linux-kernel@vger.kernel.org, pedro.falcato@gmail.com,
	stable <stable@kernel.org>
Subject: Re: [PATCH 0/2] maple_tree: Fix mas_prev() state regression.
Date: Thu, 21 Sep 2023 16:27:48 -0700	[thread overview]
Message-ID: <20230921162748.a85eb5af766e0662e4f22a5e@linux-foundation.org> (raw)
In-Reply-To: <ZQyYH+5pnDc1KYj0@casper.infradead.org>

On Thu, 21 Sep 2023 20:23:11 +0100 Matthew Wilcox <willy@infradead.org> wrote:

> > > It isn't clear what are the user-visible effects of this flaw?  Please
> > > send this along and I'll paste it in.
> > 
> > 
> > User may notice that mas_prev() or mas_next() calls that result in going
> > outside of the limit passed to the call will cause incorrect returns on
> > subsequent calls using that maple state, such as mas_find() skipping an
> > entry.
> 
> When Andrew says "User visible" he means "userspace visible".  Not
> "in kernel user visible".  What are the _consequences_.

Thanks ;)

We have a Link:
(https://gist.github.com/heatd/85d2971fae1501b55b6ea401fbbe485b) but it
takes us to the reproducer code.  If it took us to Pedro's initial bug
report then the sun would shine and birds would sing.





  reply	other threads:[~2023-09-21 23:27 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-09-21 18:12 Liam R. Howlett
2023-09-21 18:12 ` [PATCH 1/2] maple_tree: Add mas_active() to detect in-tree walks Liam R. Howlett
2023-09-21 18:12 ` [PATCH 2/2] maple_tree: Add MAS_UNDERFLOW and MAS_OVERFLOW states Liam R. Howlett
2023-09-21 18:40   ` Matthew Wilcox
2023-09-21 18:47     ` Liam R. Howlett
2023-09-21 18:25 ` [PATCH 0/2] maple_tree: Fix mas_prev() state regression Andrew Morton
2023-09-21 18:53   ` Liam R. Howlett
2023-09-21 19:23     ` Matthew Wilcox
2023-09-21 23:27       ` Andrew Morton [this message]
2023-09-21 23:34         ` Liam R. Howlett
2023-09-21 23:41           ` Pedro Falcato
2023-09-21 23:51             ` Liam R. Howlett

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