Re: [PATCH 2/2] media: v4l: vsp1: Fix uif null pointer access

From: Hans Verkuil <hverkuil-cisco@xs4all.nl>
To: Laurent Pinchart <laurent.pinchart@ideasonboard.com>,
	Biju Das <biju.das.jz@bp.renesas.com>
Cc: "kieran.bingham+renesas@ideasonboard.com" 
	<kieran.bingham+renesas@ideasonboard.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
	"linux-renesas-soc@vger.kernel.org" 
	<linux-renesas-soc@vger.kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Chris Paterson <Chris.Paterson2@renesas.com>,
	Biju Das <biju.das@bp.renesas.com>,
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@bp.renesas.com>
Subject: Re: [PATCH 2/2] media: v4l: vsp1: Fix uif null pointer access
Date: Tue, 16 Mar 2021 09:21:15 +0100	[thread overview]
Message-ID: <c757d90e-da85-6862-36fc-2343795de4b4@xs4all.nl> (raw)
In-Reply-To: <YE7XwWVZeOZ+HsYx@pendragon.ideasonboard.com>

On 15/03/2021 04:42, Laurent Pinchart wrote:
> Hi Biju,
> 
> On Wed, Mar 10, 2021 at 02:50:23PM +0000, Biju Das wrote:
>>> On 10/03/2021 13:56, Biju Das wrote:
>>>> Thanks for the feedback.
>>>>> Subject: Re: [PATCH 2/2] media: v4l: vsp1: Fix uif null pointer
>>>>> access
>>>>>
>>>>> Hi Biju,
>>>>>
>>>>> On 01/03/2021 12:08, Biju Das wrote:
>>>>>> RZ/G2L SoC has no UIF. This patch fixes null pointer access, when
>>>>>> UIF module is not used.
>>>>>>
>>>>>> Fixes: 5e824f989e6e8("media: v4l: vsp1: Integrate DISCOM in display
>>>>>> pipeline")
>>>>>> Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
>>>>>> ---
>>>>>>  drivers/media/platform/vsp1/vsp1_drm.c | 4 ++--
>>>>>>  1 file changed, 2 insertions(+), 2 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/media/platform/vsp1/vsp1_drm.c
>>>>>> b/drivers/media/platform/vsp1/vsp1_drm.c
>>>>>> index f6d2f47a4058..06f74d410973 100644
>>>>>> --- a/drivers/media/platform/vsp1/vsp1_drm.c
>>>>>> +++ b/drivers/media/platform/vsp1/vsp1_drm.c
>>>>>> @@ -462,9 +462,9 @@ static int vsp1_du_pipeline_setup_inputs(struct
>>>>>> vsp1_device *vsp1,
>>>>>
>>>>>
>>>>> This looks like it complicates these conditionals more than we
>>>>> perhaps need to.
>>>>>
>>>>> What do you think about adding something above the block comment here?:
>>>>
>>>> It is much better.
>>>>
>>>> This patch is accepted in media tree[1]. So not sure, should I send a
>>>> follow up patch as optimization or drop this patch and send new one.
>>>
>>> Oh, I didn't realise these were in already. Sorry, I didn't see any review
>>> on the list, and it was the earliest I had got to them.
>>>
>>>> Please suggest.
>>>
>>> Up to you, I don't think this would get dropped now it's integrated.
>>> It's in, so if you want to update on top I believe that's fine.
>>
>> OK, Will send follow up patch as optimization.
> 
> That would be nice.
> 
> I don't think this patch should have been fast-tracked as a fix, as
> RZ/G2L isn't supported in mainline yet as far as I can tell.
> 
> Hans, next time, could we get a notification instead of a silent merge ?

My apologies, it seemed a trivial fix, but I should have checked with you.

I jumped the gun here :-(

Regards,

	Hans

> 
>>>>> 	if (!drm_pipe->uif)
>>>>> 		return 0;
>>>>>
>>>>>
>>>>>>  	 * make sure it is present in the pipeline's list of entities if it
>>>>>>  	 * wasn't already.
>>>>>>  	 */
>>>>>> -	if (!use_uif) {
>>>>>> +	if (drm_pipe->uif && !use_uif) {
>>>>>>  		drm_pipe->uif->pipe = NULL;
>>>>>> -	} else if (!drm_pipe->uif->pipe) {
>>>>>> +	} else if (drm_pipe->uif && !drm_pipe->uif->pipe) {>
>>>>> 	drm_pipe->uif->pipe = pipe;
>>>>>>  		list_add_tail(&drm_pipe->uif->list_pipe, &pipe->entities);
>>>>>>  	}
>>>>>>
> 