linux-kernel - Re: [PATCH] Staging: rtlwifi: Remove NULL pointer dereference

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Date:   Tue, 10 Oct 2017 11:06:07 +1100
From:   "Tobin C. Harding" <me@...in.cc>
To:     Shreeya Patel <shreeya.patel23498@...il.com>
Cc:     gregkh@...uxfoundation.org, devel@...verdev.osuosl.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Staging: rtlwifi: Remove NULL pointer dereference

On Tue, Oct 10, 2017 at 02:48:58AM +0530, Shreeya Patel wrote:
> Remove NULL pointer dereference as it results in undefined
> behaviour, and will usually lead to a runtime error.

The diff does not show any pointer dereference so it is hard to understand what you are trying to do
with this patch.

> Signed-off-by: Shreeya Patel <shreeya.patel23498@...il.com>
> ---
>  drivers/staging/rtlwifi/base.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/rtlwifi/base.c b/drivers/staging/rtlwifi/base.c
> index b88b0e8..5bb8f98 100644
> --- a/drivers/staging/rtlwifi/base.c
> +++ b/drivers/staging/rtlwifi/base.c
> @@ -781,7 +781,7 @@ static void _rtl_txrate_selectmode(struct ieee80211_hw *hw,
>  
>  	struct rtl_priv *rtlpriv = rtl_priv(hw);
>  	struct rtl_mac *mac = rtl_mac(rtl_priv(hw));
> -	struct rtl_sta_info *sta_entry = NULL;
> +	struct rtl_sta_info *sta_entry;

Now the pointer just has garbage in it instead of the testable value of NULL. If you are concerned
with the dereference perhaps you could add a NULL check, again it's hard to say without seeing the
code.

It is hard to see how this patch is correct though.

Hope this helps,
Tobin.