Re: [PATCH v2] media: verisilicon: Fix crash when probing encoder

From: Benjamin Gaignard <benjamin.gaignard@collabora.com>
To: Michael Tretter <m.tretter@pengutronix.de>,
	ezequiel@vanguardiasur.com.ar, p.zabel@pengutronix.de,
	mchehab@kernel.org, m.szyprowski@samsung.com,
	linux-media@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-kernel@vger.kernel.org, kernel@collabora.com,
	kernel@pengutronix.de, nicolas.dufresne@collabora.com,
	didi.debian@cknow.org, hverkuil-cisco@xs4all.nl
Subject: Re: [PATCH v2] media: verisilicon: Fix crash when probing encoder
Date: Thu, 1 Jun 2023 16:08:13 +0200	[thread overview]
Message-ID: <2a892e71-f1be-41eb-5397-87484db7d592@collabora.com> (raw)
In-Reply-To: <20230601132749.GA31313@pengutronix.de>

Le 01/06/2023 à 15:27, Michael Tretter a écrit :
> Hi Benjamin,
>
> On Thu, 13 Apr 2023 12:47:56 +0200, Benjamin Gaignard wrote:
>> ctx->vpu_dst_fmt is no more initialized before calling hantro_try_fmt()
>> so assigne it to vpu_fmt led to crash the kernel.
>> Like for decoder case use 'fmt' as format for encoder and clean up
>> the code.
>>
>> Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
>> Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
>> Fixes: db6f68b51e5c ("media: verisilicon: Do not set context src/dst formats in reset functions")
>> ---
>> version 2:
>> - Remove useless vpu_fmt.
>>
>>   drivers/media/platform/verisilicon/hantro_v4l2.c | 10 +++-------
>>   1 file changed, 3 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/media/platform/verisilicon/hantro_v4l2.c b/drivers/media/platform/verisilicon/hantro_v4l2.c
>> index 8f1414085f47..d71f79471396 100644
>> --- a/drivers/media/platform/verisilicon/hantro_v4l2.c
>> +++ b/drivers/media/platform/verisilicon/hantro_v4l2.c
>> @@ -275,7 +275,7 @@ static int hantro_try_fmt(const struct hantro_ctx *ctx,
>>   			  struct v4l2_pix_format_mplane *pix_mp,
>>   			  enum v4l2_buf_type type)
>>   {
>> -	const struct hantro_fmt *fmt, *vpu_fmt;
>> +	const struct hantro_fmt *fmt;
>>   	bool capture = V4L2_TYPE_IS_CAPTURE(type);
>>   	bool coded;
>>   
>> @@ -295,11 +295,7 @@ static int hantro_try_fmt(const struct hantro_ctx *ctx,
>>   
>>   	if (coded) {
>>   		pix_mp->num_planes = 1;
>> -		vpu_fmt = fmt;
>> -	} else if (ctx->is_encoder) {
>> -		vpu_fmt = ctx->vpu_dst_fmt;
>> -	} else {
>> -		vpu_fmt = fmt;
>> +	} else if (!ctx->is_encoder) {
>>   		/*
>>   		 * Width/height on the CAPTURE end of a decoder are ignored and
>>   		 * replaced by the OUTPUT ones.
>> @@ -311,7 +307,7 @@ static int hantro_try_fmt(const struct hantro_ctx *ctx,
>>   	pix_mp->field = V4L2_FIELD_NONE;
>>   
>>   	v4l2_apply_frmsize_constraints(&pix_mp->width, &pix_mp->height,
>> -				       &vpu_fmt->frmsize);
>> +				       &fmt->frmsize);
> This causes a regression on the OUTPUT device of the encoder. fmt->frmsize is
> only valid for coded ("bitstream") formats, but fmt on the OUTPUT of an
> encoder will be a raw format. This results in width and height to be clamped
> to 0.
>
> I think the correct fix would be to apply the frmsize constraints of the
> currently configured coded format, but as ctx->vpu_dst_fmt is not initialized
> before calling this code, I don't know how to get the coded format.

if ctx->dst_fmt is correctly set (and it should be) then doing:

pix_mp->width = ctx->dst_fmt.width;
pix_mp->height = ctx->dst_fmt.height;

should solve the issue.

Benjamin

>
> Michael
>
>>   
>>   	if (!coded) {
>>   		/* Fill remaining fields */
>> -- 
>> 2.34.1
>>

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