From: Daniel Vetter <daniel@ffwll.ch>
To: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: "David Airlie" <airlied@linux.ie>,
"Michel Dänzer" <michel@daenzer.net>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm: Use kvzalloc for allocating blob property memory
Date: Mon, 2 Jul 2018 10:07:04 +0200 [thread overview]
Message-ID: <20180702080704.GG13978@phenom.ffwll.local> (raw)
In-Reply-To: <20180629163832.GF5565@intel.com>
On Fri, Jun 29, 2018 at 07:38:32PM +0300, Ville Syrjälä wrote:
> On Fri, Jun 29, 2018 at 06:27:28PM +0200, Michel Dänzer wrote:
> > On 2018-06-29 06:12 PM, Ville Syrjälä wrote:
> > > On Fri, Jun 29, 2018 at 04:27:10PM +0200, Michel Dänzer wrote:
> > >> From: Michel Dänzer <michel.daenzer@amd.com>
> > >>
> > >> The property size may be controlled by userspace, can be large (I've
> > >> seen failure with order 4, i.e. 16 pages / 64 KB) and doesn't need to be
> > >> physically contiguous.
> > >
> > > I wonder if we should enforce some kind of reasonable limit
> > > on the blob size. Looks like we allow anything up to
> > > ULONG_MAX currently. We can't tell at createblob time how
> > > the thing is going to be used, so can't have any kind
> > > of property specific limit unfortunately.
> >
> > The failure I was seeing was for a gamma LUT, so a size limit alone
> > cannot solve the issue.
>
> Sure. I was just thinking that maybe we shouldn't allow someone to
> allocate unlimited amounts of kernel memory via this interface. But
> to do that effectively we'd also need to limit the total amount used
> by all blobs.
People with drm master rights are allowed to pin enormous amounts of
memory (through pinning of display buffers) ... I think simply requiring
DRM_MASTER for the ioctl would be good enough. Atm anyone can abuse
createblob to waste memory, which is a bit much.
We haven't marked it with DRM_RENDER_ALLOW, so I think this is just an
oversight really. I'll type a patch.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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WARNING: multiple messages have this Message-ID (diff)
From: Daniel Vetter <daniel@ffwll.ch>
To: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: "Michel Dänzer" <michel@daenzer.net>,
"David Airlie" <airlied@linux.ie>,
linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org
Subject: Re: [PATCH] drm: Use kvzalloc for allocating blob property memory
Date: Mon, 2 Jul 2018 10:07:04 +0200 [thread overview]
Message-ID: <20180702080704.GG13978@phenom.ffwll.local> (raw)
In-Reply-To: <20180629163832.GF5565@intel.com>
On Fri, Jun 29, 2018 at 07:38:32PM +0300, Ville Syrjälä wrote:
> On Fri, Jun 29, 2018 at 06:27:28PM +0200, Michel Dänzer wrote:
> > On 2018-06-29 06:12 PM, Ville Syrjälä wrote:
> > > On Fri, Jun 29, 2018 at 04:27:10PM +0200, Michel Dänzer wrote:
> > >> From: Michel Dänzer <michel.daenzer@amd.com>
> > >>
> > >> The property size may be controlled by userspace, can be large (I've
> > >> seen failure with order 4, i.e. 16 pages / 64 KB) and doesn't need to be
> > >> physically contiguous.
> > >
> > > I wonder if we should enforce some kind of reasonable limit
> > > on the blob size. Looks like we allow anything up to
> > > ULONG_MAX currently. We can't tell at createblob time how
> > > the thing is going to be used, so can't have any kind
> > > of property specific limit unfortunately.
> >
> > The failure I was seeing was for a gamma LUT, so a size limit alone
> > cannot solve the issue.
>
> Sure. I was just thinking that maybe we shouldn't allow someone to
> allocate unlimited amounts of kernel memory via this interface. But
> to do that effectively we'd also need to limit the total amount used
> by all blobs.
People with drm master rights are allowed to pin enormous amounts of
memory (through pinning of display buffers) ... I think simply requiring
DRM_MASTER for the ioctl would be good enough. Atm anyone can abuse
createblob to waste memory, which is a bit much.
We haven't marked it with DRM_RENDER_ALLOW, so I think this is just an
oversight really. I'll type a patch.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
next prev parent reply other threads:[~2018-07-02 8:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-29 14:27 [PATCH] drm: Use kvzalloc for allocating blob property memory Michel Dänzer
2018-06-29 14:27 ` Michel Dänzer
2018-06-29 14:50 ` Alex Deucher
2018-06-29 14:50 ` Alex Deucher
2018-06-29 16:12 ` Ville Syrjälä
2018-06-29 16:12 ` Ville Syrjälä
2018-06-29 16:27 ` Michel Dänzer
2018-06-29 16:27 ` Michel Dänzer
2018-06-29 16:38 ` Ville Syrjälä
2018-06-29 16:38 ` Ville Syrjälä
2018-07-02 8:07 ` Daniel Vetter [this message]
2018-07-02 8:07 ` Daniel Vetter
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