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Date:   Wed, 2 Sep 2020 10:55:05 -0600
From:   Mathieu Poirier <mathieu.poirier@linaro.org>
To:     Nicolas Boichat <drinkcat@chromium.org>
Cc:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Pi-Hsun Shih <pihsun@chromium.org>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-mediatek@lists.infradead.org,
        linux-remoteproc@vger.kernel.org
Subject: Re: [PATCH v2] rpmsg: Avoid double-free in mtk_rpmsg_register_device
Message-ID: <20200902165505.GA280378@xps15>
References: <20200902190709.v2.1.I56cf27cd59f4013bd074dc622c8b8248b034a4cc@changeid>
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On Wed, Sep 02, 2020 at 07:07:15PM +0800, Nicolas Boichat wrote:
> If rpmsg_register_device fails, it will call
> mtk_rpmsg_release_device which already frees mdev.
> 
> Fixes: 7017996951fde84 ("rpmsg: add rpmsg support for mt8183 SCP.")

The SHA should be 12 characters instead of 15.  With that:

Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org>

> Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
> ---
> 
> Changes in v2:
>  - Drop useless if and ret variable (Markus Elfring)
> 
>  drivers/rpmsg/mtk_rpmsg.c | 9 +--------
>  1 file changed, 1 insertion(+), 8 deletions(-)
> 
> diff --git a/drivers/rpmsg/mtk_rpmsg.c b/drivers/rpmsg/mtk_rpmsg.c
> index 83f2b8804ee989d..96a17ec2914011d 100644
> --- a/drivers/rpmsg/mtk_rpmsg.c
> +++ b/drivers/rpmsg/mtk_rpmsg.c
> @@ -200,7 +200,6 @@ static int mtk_rpmsg_register_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
>  	struct rpmsg_device *rpdev;
>  	struct mtk_rpmsg_device *mdev;
>  	struct platform_device *pdev = mtk_subdev->pdev;
> -	int ret;
>  
>  	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
>  	if (!mdev)
> @@ -219,13 +218,7 @@ static int mtk_rpmsg_register_device(struct mtk_rpmsg_rproc_subdev *mtk_subdev,
>  	rpdev->dev.parent = &pdev->dev;
>  	rpdev->dev.release = mtk_rpmsg_release_device;
>  
> -	ret = rpmsg_register_device(rpdev);
> -	if (ret) {
> -		kfree(mdev);
> -		return ret;
> -	}
> -
> -	return 0;
> +	return rpmsg_register_device(rpdev);
>  }
>  
>  static void mtk_register_device_work_function(struct work_struct *register_work)
> -- 
> 2.28.0.402.g5ffc5be6b7-goog
>