From: Pedro Falcato <pedro.falcato@gmail.com>
To: "Liam R. Howlett" <Liam.Howlett@oracle.com>,
Andrew Morton <akpm@linux-foundation.org>,
Matthew Wilcox <willy@infradead.org>,
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: Fri, 22 Sep 2023 00:41:37 +0100 [thread overview]
Message-ID: <CAKbZUD3GS7YJmeO1q=f7LRomkJAigQaFw93Vwn99jZaO9O1Eyg@mail.gmail.com> (raw)
In-Reply-To: <20230921233422.kv46hm4lddhp6rgb@revolver>
On Fri, Sep 22, 2023 at 12:34 AM Liam R. Howlett
<Liam.Howlett@oracle.com> wrote:
>
> * Andrew Morton <akpm@linux-foundation.org> [230921 19:27]:
> > 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.
> >
>
> I don't think the irc channel is logged so I'll respin with a cleaner
> changelog for both patches and the subject of patch 1.
FYI:
The original distro bug report: https://bugs.archlinux.org/task/79656
The original userspace program bug report:
https://github.com/cebix/macemu/issues/271
(and yes, this is my fault, I should've raised this on the ML with the
regression tracker and all, but I tried to write my own fix then
realized it was trickier than it looked and pinged Liam)
--
Pedro
next prev parent reply other threads:[~2023-09-21 23:41 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
2023-09-21 23:34 ` Liam R. Howlett
2023-09-21 23:41 ` Pedro Falcato [this message]
2023-09-21 23:51 ` Liam R. Howlett
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