Re: [PATCH v3] staging: rtl8723bs: fix a potential memory leak in rtw_init_cmd_priv()

[Greg KH <gregkh@linuxfoundation.org>]

On Thu, Sep 08, 2022 at 03:33:00PM +0800, xkernel.wang@foxmail.com wrote:
> From: Xiaoke Wang <xkernel.wang@foxmail.com>
> 
> In rtw_init_cmd_priv(), if `pcmdpriv->rsp_allocated_buf` is allocated  
> in failure, then `pcmdpriv->cmd_allocated_buf` will be not properly 
> released. Besides, considering there are only two error paths and the 
> first one can directly return, so we do not need implicitly jump to the 
> `exit` tag to execute the error handler.
> 
> So this patch added `kfree(pcmdpriv->cmd_allocated_buf);` on the error 
> path to release the resource and simplified the return logic of 

Again, whitespace at end of changelog text :(

> rtw_init_cmd_priv(). As there is no FooBar device to test with, no runtime
> testing was performed.

"FooBar"?

> 
> Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com>
> ---
> ChangeLog:
> v1->v2 update the description.
> v2->v3 update the description.
>  drivers/staging/rtl8723bs/core/rtw_cmd.c | 17 +++++++----------
>  1 file changed, 7 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/staging/rtl8723bs/core/rtw_cmd.c b/drivers/staging/rtl8723bs/core/rtw_cmd.c
> index e574893..9126ea9 100644
> --- a/drivers/staging/rtl8723bs/core/rtw_cmd.c
> +++ b/drivers/staging/rtl8723bs/core/rtw_cmd.c
> @@ -161,8 +161,6 @@ static struct cmd_hdl wlancmds[] = {
>  
>  int rtw_init_cmd_priv(struct	cmd_priv *pcmdpriv)
>  {
> -	int res = 0;
> -
>  	init_completion(&pcmdpriv->cmd_queue_comp);
>  	init_completion(&pcmdpriv->terminate_cmdthread_comp);
>  
> @@ -175,18 +173,17 @@ int rtw_init_cmd_priv(struct	cmd_priv *pcmdpriv)
>  
>  	pcmdpriv->cmd_allocated_buf = rtw_zmalloc(MAX_CMDSZ + CMDBUFF_ALIGN_SZ);
>  
> -	if (!pcmdpriv->cmd_allocated_buf) {
> -		res = -ENOMEM;
> -		goto exit;
> -	}
> +	if (!pcmdpriv->cmd_allocated_buf)
> +		return -ENOMEM;
>  
>  	pcmdpriv->cmd_buf = pcmdpriv->cmd_allocated_buf  +  CMDBUFF_ALIGN_SZ - ((SIZE_PTR)(pcmdpriv->cmd_allocated_buf) & (CMDBUFF_ALIGN_SZ-1));
>  
>  	pcmdpriv->rsp_allocated_buf = rtw_zmalloc(MAX_RSPSZ + 4);
>  
>  	if (!pcmdpriv->rsp_allocated_buf) {
> -		res = -ENOMEM;
> -		goto exit;
> +		kfree(pcmdpriv->cmd_allocated_buf);
> +		pcmdpriv->cmd_allocated_buf = NULL;

Why does this have to be set to NULL?

thanks,

greg k-h