From: Andrew Morton <akpm@linux-foundation.org>
To: Luis Chamberlain <mcgrof@kernel.org>
Cc: ziy@nvidia.com, linux-mm@kvack.org, fstests@vger.kernel.org,
linux-xfs@vger.kernel.org, linux-kernel@vger.kernel.org,
willy@infradead.org, hare@suse.de, john.g.garry@oracle.com,
p.raghav@samsung.com, da.gomez@samsung.com
Subject: Re: [PATCH 1/2] mm/huge_memory: skip invalid debugfs file entry for folio split
Date: Mon, 29 Apr 2024 09:23:07 -0700 [thread overview]
Message-ID: <20240429092307.37bf51c79f70bad4922f6277@linux-foundation.org> (raw)
In-Reply-To: <Zi8cYrtxyO7Uw-Mc@bombadil.infradead.org>
On Sun, 28 Apr 2024 21:04:50 -0700 Luis Chamberlain <mcgrof@kernel.org> wrote:
> On Thu, Apr 25, 2024 at 02:01:26PM -0700, Andrew Morton wrote:
> > On Wed, 24 Apr 2024 15:54:48 -0700 Luis Chamberlain <mcgrof@kernel.org> wrote:
> >
> > > If the file entry is too long we may easily end up going out of bounds
> > > and crash after strsep() on sscanf().
> > >
> >
> > Can you explain why? I'm not seeing it.
>
> I couldn't see it either but I just looked at the crash below and
> its the only thing I could think of. So I think its when userspace
> somehow abuses MAX_INPUT_BUF_SZ a lot somehow.
This isn't a good basis for making kernel changes :(
Can you investigate a little further please? What actually is present
at *buf when your new checks succeed? Could we be seeing 0xNNN,0xNNN
and leaving new_order unaltered? Or something.
next prev parent reply other threads:[~2024-04-29 16:23 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-24 22:54 [PATCH 0/2] mm/huge_memory: couple fixes and one cleanup Luis Chamberlain
2024-04-24 22:54 ` [PATCH 1/2] mm/huge_memory: skip invalid debugfs file entry for folio split Luis Chamberlain
2024-04-25 1:03 ` Zi Yan
2024-04-25 22:40 ` Luis Chamberlain
2024-04-25 21:01 ` Andrew Morton
2024-04-29 4:04 ` Luis Chamberlain
2024-04-29 16:23 ` Andrew Morton [this message]
2024-05-07 0:30 ` Luis Chamberlain
2024-04-24 22:54 ` [PATCH 2/2] mm/huge_memory: cap max length on debugfs file entry " Luis Chamberlain
2024-04-25 1:05 ` Zi Yan
2024-04-24 22:55 ` [PATCH 0/2] mm/huge_memory: couple fixes and one cleanup Luis Chamberlain
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