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Message-ID: <2e878a04-e86a-35d3-546d-34e4c1bafe19@quicinc.com>
Date:   Tue, 13 Dec 2022 13:41:25 -0800
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Subject: Re: [PATCH] drm/msm/dpu: check for null return of devm_kzalloc() in
 dpu_writeback_init()
Content-Language: en-US
To:     Hui Tang <tanghui20@huawei.com>, <robdclark@gmail.com>,
        <dmitry.baryshkov@linaro.org>, <airlied@gmail.com>,
        <daniel@ffwll.ch>
CC:     <linux-arm-msm@vger.kernel.org>, <dri-devel@lists.freedesktop.org>,
        <freedreno@lists.freedesktop.org>, <linux-kernel@vger.kernel.org>,
        <yusongping@huawei.com>
References: <20221119055518.179937-1-tanghui20@huawei.com>
From:   Abhinav Kumar <quic_abhinavk@quicinc.com>
In-Reply-To: <20221119055518.179937-1-tanghui20@huawei.com>
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On 11/18/2022 9:55 PM, Hui Tang wrote:
> Because of the possilble failure of devm_kzalloc(), dpu_wb_conn might
> be NULL and will cause null pointer derefrence later.
derefrence --> dereference
> 
> Therefore, it might be better to check it and directly return -ENOMEM.
> 
> Fixes: 77b001acdcfe ("drm/msm/dpu: add the writeback connector layer")
> Signed-off-by: Hui Tang <tanghui20@huawei.com>

With that nit fixed,

Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
> ---
>   drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> index 088ec990a2f2..2a5a68366582 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
> @@ -70,6 +70,8 @@ int dpu_writeback_init(struct drm_device *dev, struct drm_encoder *enc,
>   	int rc = 0;
>   
>   	dpu_wb_conn = devm_kzalloc(dev->dev, sizeof(*dpu_wb_conn), GFP_KERNEL);
> +	if (!dpu_wb_conn)
> +		return -ENOMEM;
>   
>   	drm_connector_helper_add(&dpu_wb_conn->base.base, &dpu_wb_conn_helper_funcs);
>