From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Boris Brezillon <boris.brezillon@collabora.com>
Cc: dri-devel@lists.freedesktop.org, Rob Herring <robh+dt@kernel.org>,
Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
Steven Price <steven.price@arm.com>
Subject: Re: [PATCH v2] drm/panfrost: Document base field location constraint in panfrost_gem_object
Date: Fri, 29 Nov 2019 16:28:57 +0200 [thread overview]
Message-ID: <20191129142857.GE1208@intel.com> (raw)
In-Reply-To: <20191129135614.2439058-1-boris.brezillon@collabora.com>
On Fri, Nov 29, 2019 at 02:56:14PM +0100, Boris Brezillon wrote:
> I've spent hours chasing a memory corruption that was caused by
> insertion of an extra field field before ->base. Let's document the
> fact that base has to be the first field in panfrost_gem_object.
>
> Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
> ---
> Changes in v2:
> * Use the proper prefix in the subject line
> ---
> drivers/gpu/drm/panfrost/panfrost_gem.h | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/panfrost/panfrost_gem.h b/drivers/gpu/drm/panfrost/panfrost_gem.h
> index b3517ff9630c..d480261fc177 100644
> --- a/drivers/gpu/drm/panfrost/panfrost_gem.h
> +++ b/drivers/gpu/drm/panfrost/panfrost_gem.h
> @@ -10,6 +10,10 @@
> struct panfrost_mmu;
>
> struct panfrost_gem_object {
> + /*
> + * Must be the first element because we're using some of the
> + * drm_gem_shmem helpers.
> + */
An accompanying BUILD_BUG_ON() would be a good way to catch anyone
ignoring the comment.
> struct drm_gem_shmem_object base;
> struct sg_table *sgts;
>
> --
> 2.23.0
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Ville Syrjälä
Intel
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prev parent reply other threads:[~2019-11-29 14:29 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-29 13:56 [PATCH v2] drm/panfrost: Document base field location constraint in panfrost_gem_object Boris Brezillon
2019-11-29 14:13 ` Steven Price
2019-11-29 14:19 ` Boris Brezillon
2019-11-29 18:40 ` Daniel Vetter
2019-11-29 19:24 ` Boris Brezillon
2019-11-29 19:43 ` Ville Syrjälä
2019-11-29 22:23 ` Boris Brezillon
2019-11-29 14:16 ` Alyssa Rosenzweig
2019-11-29 14:28 ` Ville Syrjälä [this message]
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