linux-kernel - Re: [PATCH] dma-buf: add reference counting for exporter module

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Wed, 8 Aug 2012 16:06:38 +0200
From:	Daniel Vetter <daniel@...ll.ch>
To:	Tomasz Stanislawski <t.stanislaws@...sung.com>
Cc:	Laurent Pinchart <laurent.pinchart@...asonboard.com>,
	dri-devel@...ts.freedesktop.org, linaro-mm-sig@...ts.linaro.org,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	devel@...verdev.osuosl.org, Pawel Osciak <pawel@...iak.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jerome Glisse <jglisse@...hat.com>,
	Vinod Koul <vinod.koul@...el.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	Rob Landley <rob@...dley.net>,
	Daniel Vetter <daniel.vetter@...ll.ch>,
	Alex Deucher <alexander.deucher@....com>,
	Rob Clark <rob@...com>,
	Dan Williams <dan.j.williams@...el.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Sumit Semwal <sumit.semwal@...aro.org>,
	linux-media@...r.kernel.org
Subject: Re: [PATCH] dma-buf: add reference counting for exporter module

On Wed, Aug 08, 2012 at 03:53:10PM +0200, Tomasz Stanislawski wrote:
> Hi Laurent,
> 
> On 08/08/2012 03:35 PM, Laurent Pinchart wrote:
> > Hi Tomasz,
> > 
> > Thanks for the patch.
> > 
> > On Wednesday 08 August 2012 12:17:41 Tomasz Stanislawski wrote:
> >> This patch adds reference counting on a module that exports dma-buf and
> >> implements its operations. This prevents the module from being unloaded
> >> while DMABUF file is in use.
> >>
> >> Signed-off-by: Tomasz Stanislawski <t.stanislaws@...sung.com>
> >> ---
> >>  Documentation/dma-buf-sharing.txt          |    3 ++-
> >>  drivers/base/dma-buf.c                     |   10 +++++++++-
> >>  drivers/gpu/drm/exynos/exynos_drm_dmabuf.c |    1 +
> >>  drivers/gpu/drm/i915/i915_gem_dmabuf.c     |    1 +
> >>  drivers/gpu/drm/nouveau/nouveau_prime.c    |    1 +
> >>  drivers/gpu/drm/radeon/radeon_prime.c      |    1 +
> >>  drivers/staging/omapdrm/omap_gem_dmabuf.c  |    1 +
> >>  include/linux/dma-buf.h                    |    2 ++
> >>  8 files changed, 18 insertions(+), 2 deletions(-)
> >>
> [snip]
> 
> >> @@ -96,6 +98,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct
> >> dma_buf_ops *ops, struct file *file;
> >>
> >>  	if (WARN_ON(!priv || !ops
> >> +			  || !ops->owner
> 
> Thank you for spotting this.
> I didn'y know that try_get_module returned true is module was NULL.
> 
> BTW. Is it worth to add ".owner = THIS_MODULE," to all dma_buf
> exporters in this patch?

Yeah, I think that makes sense. Otherwise it might get lost somewhere,
i.e. you can smash my Ack on this.
-Daniel
-- 
Daniel Vetter
Mail: daniel@...ll.ch
Mobile: +41 (0)79 365 57 48
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/