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Date:   Mon, 12 Sep 2022 09:35:40 +0200
From:   Martin Kaiser <martin@kaiser.cx>
To:     xkernel.wang@foxmail.com
Cc:     Larry.Finger@lwfinger.net, phil@philpotter.co.uk,
        gregkh@linuxfoundation.org, philipp.g.hortmann@gmail.com,
        linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v5] staging: r8188eu: add kfree() on an error path of
 rtw_xmit_resource_alloc()
Message-ID: <20220912073540.l7z56kgjde47r3pr@viti.kaiser.cx>
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Thus wrote xkernel.wang@foxmail.com (xkernel.wang@foxmail.com):

> From: Xiaoke Wang <xkernel.wang@foxmail.com>

> In rtw_xmit_resource_alloc(), if usb_alloc_urb() fails, then the memory
> `pxmitbuf->pallocated_buf` which is allocated by kzalloc() is not properly
> released before returning.
> So this patch adds kfree() on the above error path to release it in time.

> Tested-by: Philipp Hortmann <philipp.g.hortmann@gmail.com> # Edimax N150
> Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
> ---
> ChangeLog:
> v1->v2 update the description.
> v2->v3 rebase.
> v3->v4 update the description.
> v4->v5 rebase and update the corresponding subject and description.
> Note that the original function name was changed, so the subject of this
> patch is updated from "[PATCH v4] staging: r8188eu: fix potential memory
> leak in rtw_os_xmit_resource_alloc()" to "[PATCH v5] staging: r8188eu: add
> kfree() on an error path of rtw_xmit_resource_alloc()".
> In addition, thanks to Philipp Hortmann for his testing and advice.
>  drivers/staging/r8188eu/core/rtw_xmit.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)

> diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
> index 67f9c05..9c39d08 100644
> --- a/drivers/staging/r8188eu/core/rtw_xmit.c
> +++ b/drivers/staging/r8188eu/core/rtw_xmit.c
> @@ -44,8 +44,10 @@ static int rtw_xmit_resource_alloc(struct adapter *padapter, struct xmit_buf *px
>  	pxmitbuf->dma_transfer_addr = 0;

>  	pxmitbuf->pxmit_urb = usb_alloc_urb(0, GFP_KERNEL);
> -	if (!pxmitbuf->pxmit_urb)
> +	if (!pxmitbuf->pxmit_urb) {
> +		kfree(pxmitbuf->pallocated_buf);
>  		return _FAIL;
> +	}

>  	return _SUCCESS;
>  }
> -- 

Reviewed-by: Martin Kaiser <martin@kaiser.cx>