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From:   Tony Chuang <yhchuang@realtek.com>
To:     Brian Norris <briannorris@chromium.org>,
        "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: RE: [PATCH] rtw88: don't treat NULL pointer as an array
Thread-Topic: [PATCH] rtw88: don't treat NULL pointer as an array
Thread-Index: AQHWeAB4uJN/vdOmkEGwwlrKe37FlalGgY2A
Date:   Mon, 24 Aug 2020 01:50:32 +0000
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References: <20200821211716.1631556-1-briannorris@chromium.org>
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> 
> I'm not a standards expert, but this really looks to be undefined
> behavior, when chip->dig_cck may be NULL. (And, we're trying to do a
> NULL check a few lines down, because some chip variants will use NULL.)
> 
> Fixes: fc637a860a82 ("rtw88: 8723d: Set IG register for CCK rate")

Acked-by: Yan-Hsuan Chuang <yhchuang@realtek.com>
> Signed-off-by: Brian Norris <briannorris@chromium.org>
> ---
>  drivers/net/wireless/realtek/rtw88/phy.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw88/phy.c
> b/drivers/net/wireless/realtek/rtw88/phy.c
> index 8d93f3159746..9687b376d221 100644
> --- a/drivers/net/wireless/realtek/rtw88/phy.c
> +++ b/drivers/net/wireless/realtek/rtw88/phy.c
> @@ -147,12 +147,13 @@ void rtw_phy_dig_write(struct rtw_dev *rtwdev, u8
> igi)
>  {
>  	struct rtw_chip_info *chip = rtwdev->chip;
>  	struct rtw_hal *hal = &rtwdev->hal;
> -	const struct rtw_hw_reg *dig_cck = &chip->dig_cck[0];
>  	u32 addr, mask;
>  	u8 path;
> 
> -	if (dig_cck)
> +	if (chip->dig_cck) {
> +		const struct rtw_hw_reg *dig_cck = &chip->dig_cck[0];
>  		rtw_write32_mask(rtwdev, dig_cck->addr, dig_cck->mask, igi >> 1);
> +	}
> 
>  	for (path = 0; path < hal->rf_path_num; path++) {
>  		addr = chip->dig[path].addr;

Thanks.
Yen-Hsuan