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Message-ID: <31940cd3086bc6e40f3eb9c7b923dd38131d37dd.camel@collabora.com>
Subject: Re: [PATCH] drivers/media/v4l2-core/v4l2-h264.c : add detection of
 null pointers
From:   Nicolas Dufresne <nicolas.dufresne@collabora.com>
To:     Dong Chuanjian <chuanjian@nfschina.com>, mchehab@kernel.org,
        hverkuil-cisco@xs4all.nl, sebastian.fricke@collabora.com,
        ezequiel@vanguardiasur.com.ar
Cc:     linux-media@vger.kernel.org, linux-kernel@vger.kernel.org
Date:   Mon, 09 Jan 2023 16:22:33 -0500
In-Reply-To: <20221226061711.3988-1-chuanjian@nfschina.com>
References: <20221226061711.3988-1-chuanjian@nfschina.com>
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Hi,

Le lundi 26 d=C3=A9cembre 2022 =C3=A0 14:17 +0800, Dong Chuanjian a =C3=A9c=
rit=C2=A0:
> Continue the program when the pointer assignment is successful.
>=20
> Signed-off-by: Dong Chuanjian <chuanjian@nfschina.com>
>=20
> diff --git a/drivers/media/v4l2-core/v4l2-h264.c b/drivers/media/v4l2-cor=
e/v4l2-h264.c
> index 72bd64f65198..1163cd48ff33 100644
> --- a/drivers/media/v4l2-core/v4l2-h264.c
> +++ b/drivers/media/v4l2-core/v4l2-h264.c
> @@ -343,18 +343,19 @@ static const char *format_ref_list_b(const struct v=
4l2_h264_reflist_builder *bui
>  	int n =3D 0, i;
> =20
>  	*out_str =3D kmalloc(tmp_str_size, GFP_KERNEL);

Can't this patch be reduced to this ?

+	if (!*out_str)
+		return NULL;

>=20
>=20
> -
> -	n +=3D snprintf(*out_str + n, tmp_str_size - n, "|");
> -
> -	for (i =3D 0; i < builder->num_valid; i++) {
> -		int frame_num =3D builder->refs[reflist[i].index].frame_num;
> -		u32 poc =3D v4l2_h264_get_poc(builder, reflist + i);
> -		bool longterm =3D builder->refs[reflist[i].index].longterm;
> -
> -		n +=3D scnprintf(*out_str + n, tmp_str_size - n, "%i%c%c|",
> -			       longterm ? frame_num : poc,
> -			       longterm ? 'l' : 's',
> -			       ref_type_to_char(reflist[i].fields));
> +	if (*out_str !=3D NULL) {
> +		n +=3D snprintf(*out_str + n, tmp_str_size - n, "|");
> +
> +		for (i =3D 0; i < builder->num_valid; i++) {
> +			int frame_num =3D builder->refs[reflist[i].index].frame_num;
> +			u32 poc =3D v4l2_h264_get_poc(builder, reflist + i);
> +			bool longterm =3D builder->refs[reflist[i].index].longterm;
> +
> +			n +=3D scnprintf(*out_str + n, tmp_str_size - n, "%i%c%c|",
> +				       longterm ? frame_num : poc,
> +				       longterm ? 'l' : 's',
> +				       ref_type_to_char(reflist[i].fields));
> +		}
>  	}
> =20
>  	return *out_str;