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Date: Tue, 2 Apr 2024 14:21:19 +0200
From: Boris Brezillon <boris.brezillon@collabora.com>
To: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Steven Price <steven.price@arm.com>, Liviu Dudau <liviu.dudau@arm.com>,
 Maarten Lankhorst <maarten.lankhorst@linux.intel.com>, Maxime Ripard
 <mripard@kernel.org>, Thomas Zimmermann <tzimmermann@suse.de>, David Airlie
 <airlied@gmail.com>, Daniel Vetter <daniel@ffwll.ch>, Heiko Stuebner
 <heiko@sntech.de>, dri-devel@lists.freedesktop.org,
 linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] drm/panthor: Fix off by one in
 panthor_fw_get_cs_iface()
Message-ID: <20240402142119.436dcfb6@collabora.com>
In-Reply-To: <62835c16-c85c-483d-a8fe-63be78d49d15@moroto.mountain>
References: <62835c16-c85c-483d-a8fe-63be78d49d15@moroto.mountain>
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On Tue, 2 Apr 2024 12:56:42 +0300
Dan Carpenter <dan.carpenter@linaro.org> wrote:

> The ->iface.streams[csg_slot][] array has MAX_CS_PER_CSG elements so
> this > comparison needs to be >= to prevent an out of bounds access.
> 
> Fixes: 2718d91816ee ("drm/panthor: Add the FW logical block")
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>

Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>

> ---
>  drivers/gpu/drm/panthor/panthor_fw.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/panthor/panthor_fw.c b/drivers/gpu/drm/panthor/panthor_fw.c
> index 33c87a59834e..181395e2859a 100644
> --- a/drivers/gpu/drm/panthor/panthor_fw.c
> +++ b/drivers/gpu/drm/panthor/panthor_fw.c
> @@ -308,7 +308,7 @@ panthor_fw_get_csg_iface(struct panthor_device *ptdev, u32 csg_slot)
>  struct panthor_fw_cs_iface *
>  panthor_fw_get_cs_iface(struct panthor_device *ptdev, u32 csg_slot, u32 cs_slot)
>  {
> -	if (drm_WARN_ON(&ptdev->base, csg_slot >= MAX_CSGS || cs_slot > MAX_CS_PER_CSG))
> +	if (drm_WARN_ON(&ptdev->base, csg_slot >= MAX_CSGS || cs_slot >= MAX_CS_PER_CSG))
>  		return NULL;
>  
>  	return &ptdev->fw->iface.streams[csg_slot][cs_slot];