From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: "Nicolas Dufresne" <nicolas.dufresne@collabora.com>,
"Bryan O'Donoghue" <bryan.odonoghue@linaro.org>,
"Dmitry Baryshkov" <dmitry.baryshkov@linaro.org>,
"Hans de Goede" <hdegoede@redhat.com>,
"Sumit Semwal" <sumit.semwal@linaro.org>,
"Benjamin Gaignard" <benjamin.gaignard@collabora.com>,
"Brian Starkey" <Brian.Starkey@arm.com>,
"John Stultz" <jstultz@google.com>,
"T.J. Mercier" <tjmercier@google.com>,
"Christian König" <christian.koenig@amd.com>,
"Lennart Poettering" <mzxreary@0pointer.de>,
"Robert Mader" <robert.mader@collabora.com>,
"Sebastien Bacher" <sebastien.bacher@canonical.com>,
"Linux Media Mailing List" <linux-media@vger.kernel.org>,
"dri-devel@lists.freedesktop.org"
<dri-devel@lists.freedesktop.org>,
linaro-mm-sig@lists.linaro.org,
"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
"Milan Zamazal" <mzamazal@redhat.com>,
"Maxime Ripard" <mripard@redhat.com>,
"Andrey Konovalov" <andrey.konovalov.ynk@gmail.com>
Subject: Re: Safety of opening up /dev/dma_heap/* to physically present users (udev uaccess tag) ?
Date: Thu, 9 May 2024 00:51:06 +0300 [thread overview]
Message-ID: <20240508215106.GA24860@pendragon.ideasonboard.com> (raw)
In-Reply-To: <Zjs5eM-rRoh6WYYu@phenom.ffwll.local>
On Wed, May 08, 2024 at 10:36:08AM +0200, Daniel Vetter wrote:
> On Tue, May 07, 2024 at 04:07:39PM -0400, Nicolas Dufresne wrote:
> > Le mardi 07 mai 2024 à 21:36 +0300, Laurent Pinchart a écrit :
> > > Shorter term, we have a problem to solve, and the best option we have
> > > found so far is to rely on dma-buf heaps as a backend for the frame
> > > buffer allocatro helper in libcamera for the use case described above.
> > > This won't work in 100% of the cases, clearly. It's a stop-gap measure
> > > until we can do better.
> >
> > Considering the security concerned raised on this thread with dmabuf heap
> > allocation not be restricted by quotas, you'd get what you want quickly with
> > memfd + udmabuf instead (which is accounted already).
> >
> > It was raised that distro don't enable udmabuf, but as stated there by Hans, in
> > any cases distro needs to take action to make the softISP works. This
> > alternative is easy and does not interfere in anyway with your future plan or
> > the libcamera API. You could even have both dmabuf heap (for Raspbian) and the
> > safer memfd+udmabuf for the distro with security concerns.
> >
> > And for the long term plan, we can certainly get closer by fixing that issue
> > with accounting. This issue also applied to v4l2 io-ops, so it would be nice to
> > find common set of helpers to fix these exporters.
>
> Yeah if this is just for softisp, then memfd + udmabuf is also what I was
> about to suggest. Not just as a stopgap, but as the real official thing.
Long term I still want a centralized memory allocator, at which point
libcamera should stop allocating buffers at all.
> udmabuf does kinda allow you to pin memory, but we can easily fix that by
> adding the right accounting and then either let mlock rlimits or cgroups
> kernel memory limits enforce good behavior.
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2024-05-08 21:51 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 11:49 Safety of opening up /dev/dma_heap/* to physically present users (udev uaccess tag) ? Hans de Goede
2024-05-06 12:05 ` Maxime Ripard
2024-05-06 12:11 ` Hans de Goede
2024-05-06 13:38 ` Daniel Vetter
2024-05-06 14:01 ` Hans de Goede
2024-05-07 11:15 ` Daniel Vetter
2024-05-08 5:46 ` Daniel Stone
2024-05-08 8:33 ` Daniel Vetter
2024-05-08 8:38 ` Daniel Stone
2024-05-08 15:49 ` Daniel Vetter
2024-05-09 9:23 ` Daniel Stone
2024-05-16 10:18 ` Daniel Vetter
2024-05-13 13:51 ` Simon Ser
2024-05-16 10:13 ` Daniel Vetter
2024-05-16 11:49 ` Christian König
2024-05-07 13:34 ` Dmitry Baryshkov
2024-05-07 18:59 ` Laurent Pinchart
2024-05-22 13:34 ` Maxime Ripard
2024-05-23 9:41 ` Daniel Vetter
2024-05-07 13:32 ` Dmitry Baryshkov
2024-05-07 14:34 ` Hans de Goede
2024-05-07 15:09 ` Dmitry Baryshkov
2024-05-07 15:15 ` Bryan O'Donoghue
2024-05-07 15:19 ` Dmitry Baryshkov
2024-05-07 18:40 ` Laurent Pinchart
2024-05-07 19:59 ` Dmitry Baryshkov
2024-05-07 20:15 ` Laurent Pinchart
2024-05-08 8:39 ` Daniel Vetter
2024-05-08 21:54 ` Laurent Pinchart
2024-05-13 8:39 ` Maxime Ripard
2024-05-07 17:36 ` Daniel Vetter
2024-05-07 18:36 ` Laurent Pinchart
2024-05-07 20:07 ` Nicolas Dufresne
2024-05-08 8:36 ` Daniel Vetter
2024-05-08 21:51 ` Laurent Pinchart [this message]
2024-05-08 21:52 ` Laurent Pinchart
2024-05-13 8:29 ` Maxime Ripard
2024-05-13 8:34 ` Laurent Pinchart
2024-05-13 15:10 ` Nicolas Dufresne
2024-05-14 20:42 ` Laurent Pinchart
2024-05-15 17:43 ` nicolas.dufresne
2024-05-16 11:27 ` Laurent Pinchart
2024-05-16 17:11 ` nicolas.dufresne
2024-05-21 8:43 ` Maxime Ripard
2024-05-21 14:18 ` nicolas.dufresne
2024-05-16 7:00 ` Simon Ser
2024-05-16 11:20 ` Laurent Pinchart
2024-05-22 13:02 ` Nicolas Dufresne
2024-05-13 13:42 ` Nicolas Dufresne
2024-05-13 13:51 ` Maxime Ripard
2024-05-13 15:06 ` Nicolas Dufresne
2024-05-14 20:45 ` Laurent Pinchart
2024-05-14 20:52 ` Nicolas Dufresne
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