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Message-ID: <f6421e8f75a030222bf9cc7ef191648f7495a511.camel@perches.com>
Subject: Re: [PATCH 12/12] staging: r8188eu: check the return of kzalloc()
From:   Joe Perches <joe@perches.com>
To:     xkernel.wang@foxmail.com, Larry.Finger@lwfinger.net,
        phil@philpotter.co.uk, gregkh@linuxfoundation.org
Cc:     linux-staging@lists.linux.dev, linux-kernel@vger.kernel.org
Date:   Tue, 03 May 2022 00:08:46 -0700
In-Reply-To: <tencent_702C3C4AA9F65F0EE48859211795E3800205@qq.com>
References: <tencent_A80380E4306BE7BA73E450F084232B4DFC0A@qq.com>
         <tencent_702C3C4AA9F65F0EE48859211795E3800205@qq.com>
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On Tue, 2022-05-03 at 15:02 +0800, xkernel.wang@foxmail.com wrote:
> From: Xiaoke Wang <xkernel.wang@foxmail.com>
> 
> kzalloc() is a memory allocation function which can return NULL when
> some internal memory errors happen. So it is better to handle the return
> of it to prevent potential wrong memory access.
> 
> Besides, to propagate the error to the caller, the type of
> rtw_alloc_hwxmits() is changed to `int` and another check is added to
> its caller.
> Then if kzalloc() fails, the caller will properly jump to the
> corresponding error hanlding code.

It'd be better to use the typical error returns

> diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
[]
> @@ -176,7 +176,9 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
> ?
> ?	pxmitpriv->free_xmit_extbuf_cnt = num_xmit_extbuf;
> ?
> -	rtw_alloc_hwxmits(padapter);
> +	res = rtw_alloc_hwxmits(padapter);
> +	if (res == _FAIL)
> +		goto free_xmit_extbuf;

	if (res)
		goto free_xmit_extbuf;

[]

> -void rtw_alloc_hwxmits(struct adapter *padapter)
> +int rtw_alloc_hwxmits(struct adapter *padapter)
> ?{
> ?	struct hw_xmit *hwxmits;
> ?	struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
> @@ -1495,6 +1497,8 @@ void rtw_alloc_hwxmits(struct adapter *padapter)
> ?	pxmitpriv->hwxmit_entry = HWXMIT_ENTRY;
> ?
> ?	pxmitpriv->hwxmits = kzalloc(sizeof(struct hw_xmit) * pxmitpriv->hwxmit_entry, GFP_KERNEL);
> +	if (!pxmitpriv->hwxmits)

		return -ENOMEM;