From: Rob Herring <robh@kernel.org>
To: Steven Price <steven.price@arm.com>
Cc: Daniel Vetter <daniel@ffwll.ch>, David Airlie <airlied@linux.ie>,
Tomeu Vizoso <tomeu.vizoso@collabora.com>,
Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
Boris Brezillon <boris.brezillon@collabora.com>,
dri-devel <dri-devel@lists.freedesktop.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Dan Carpenter <dan.carpenter@oracle.com>
Subject: Re: [PATCH] drm/panfrost: Avoid user size passed to kvmalloc()
Date: Thu, 16 Dec 2021 11:12:42 -0600 [thread overview]
Message-ID: <CAL_JsqKZBsJxy8h5EQf0wwfioWS-Kx9i=0cQ7p4FHckEXstGiw@mail.gmail.com> (raw)
In-Reply-To: <20211216161603.983711-1-steven.price@arm.com>
On Thu, Dec 16, 2021 at 10:16 AM Steven Price <steven.price@arm.com> wrote:
>
> panfrost_copy_in_sync() takes the number of fences from user space
> (in_sync_count) and used to kvmalloc() an array to hold that number of
> fences before processing them. This provides an easy method for user
> space to trigger the OOM killer (by temporarily allocating large amounts
> of kernel memory) or hit the WARN_ONCE() added by 7661809d493b ("mm:
> don't allow oversized kvmalloc() calls").
>
> Since we don't expect there to be a large number of fences we can
> instead iterate over the fences one-by-one and avoid the temporary
> allocation altogether. This also makes the code simpler.
Doesn't the BO lookup suffer from the same issue?
Rob
next prev parent reply other threads:[~2021-12-16 17:13 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-12-16 16:16 [PATCH] drm/panfrost: Avoid user size passed to kvmalloc() Steven Price
2021-12-16 17:12 ` Rob Herring [this message]
2021-12-17 8:55 ` Steven Price
2021-12-17 9:10 ` Dan Carpenter
2021-12-17 9:16 ` Steven Price
2021-12-17 9:28 ` Dan Carpenter
2021-12-17 9:48 ` Steven Price
2021-12-16 17:49 ` Alyssa Rosenzweig
2021-12-17 6:40 ` Dan Carpenter
2021-12-17 7:38 ` Tomeu Vizoso
2021-12-17 8:56 ` Steven Price
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