linux-kernel - Re: [PATCH 1/2] staging: r8188eu: properly handle the kzalloc()

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Message-ID: <20220331063733.GJ3293@kadam>
Date:   Thu, 31 Mar 2022 09:37:33 +0300
From:   Dan Carpenter <dan.carpenter@...cle.com>
To:     xkernel.wang@...mail.com
Cc:     Larry.Finger@...inger.net, phil@...lpotter.co.uk,
        gregkh@...uxfoundation.org, linux-staging@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] staging: r8188eu: properly handle the kzalloc()

On Wed, Mar 30, 2022 at 11:16:07PM +0800, xkernel.wang@...mail.com wrote:
> diff --git a/drivers/staging/r8188eu/core/rtw_p2p.c b/drivers/staging/r8188eu/core/rtw_p2p.c
> index e2b6cf2..f1a5df8 100644
> --- a/drivers/staging/r8188eu/core/rtw_p2p.c
> +++ b/drivers/staging/r8188eu/core/rtw_p2p.c
> @@ -27,15 +27,14 @@ static u32 go_add_group_info_attr(struct wifidirect_info *pwdinfo, u8 *pbuf)
>  	struct list_head *phead, *plist;
>  	u32 len = 0;
>  	u16 attr_len = 0;
> -	u8 tmplen, *pdata_attr, *pstart, *pcur;
> +	u8 pdata_attr[MAX_P2P_IE_LEN] = { 0x00 };
> +	u8 tmplen, *pstart, *pcur;
>  	struct sta_info *psta = NULL;
>  	struct adapter *padapter = pwdinfo->padapter;
>  	struct sta_priv *pstapriv = &padapter->stapriv;
>  
>  	DBG_88E("%s\n", __func__);
>  
> -	pdata_attr = kzalloc(MAX_P2P_IE_LEN, GFP_KERNEL);
> -
>  	pstart = pdata_attr;
>  	pcur = pdata_attr;
>  
> @@ -106,7 +105,6 @@ static u32 go_add_group_info_attr(struct wifidirect_info *pwdinfo, u8 *pbuf)
>  	if (attr_len > 0)
>  		len = rtw_set_p2p_attr_content(pbuf, P2P_ATTR_GROUP_INFO, attr_len, pdata_attr);
>  
> -	kfree(pdata_attr);
>  	return len;
>  }
>  

This part is fine.  This change is can be pulled into a separate patch
and reviewed by itself.

> diff --git a/drivers/staging/r8188eu/core/rtw_xmit.c b/drivers/staging/r8188eu/core/rtw_xmit.c
> index 46fe62c..5888979 100644
> --- a/drivers/staging/r8188eu/core/rtw_xmit.c
> +++ b/drivers/staging/r8188eu/core/rtw_xmit.c
> @@ -179,7 +179,9 @@ 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 exit;

There needs to be some cleanup if rtw_alloc_hwxmits() fails.

>  	rtw_init_hwxmits(pxmitpriv->hwxmits, pxmitpriv->hwxmit_entry);
>  
>  	for (i = 0; i < 4; i++)
> @@ -202,7 +204,6 @@ s32	_rtw_init_xmit_priv(struct xmit_priv *pxmitpriv, struct adapter *padapter)
>  	rtw_hal_init_xmit_priv(padapter);
>  
>  exit:
> -
>  	return res;

This whitespace change has nothing to do with allocating memory.  Leave
it out.

>  }
>  
> @@ -1516,7 +1517,7 @@ s32 rtw_xmit_classifier(struct adapter *padapter, struct xmit_frame *pxmitframe)
>  	return res;
>  }
>  
> -void rtw_alloc_hwxmits(struct adapter *padapter)
> +s32 rtw_alloc_hwxmits(struct adapter *padapter)
>  {
>  	struct hw_xmit *hwxmits;
>  	struct xmit_priv *pxmitpriv = &padapter->xmitpriv;
> @@ -1525,6 +1526,9 @@ void rtw_alloc_hwxmits(struct adapter *padapter)
>  
>  	pxmitpriv->hwxmits = kzalloc(sizeof(struct hw_xmit) * pxmitpriv->hwxmit_entry, GFP_KERNEL);
>  
> +	if (!pxmitpriv->hwxmits)

Don't leave a blank line between the allocation and the check.

> +		return _FAIL;
> +
>  	hwxmits = pxmitpriv->hwxmits;
>  
>  	if (pxmitpriv->hwxmit_entry == 5) {

regards,
dan carpenter