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Date:   Mon, 6 May 2019 10:42:21 +0200
From:   Stanislaw Gruszka <sgruszka@redhat.com>
To:     linux-wireless@vger.kernel.org, Kalle Valo <kvalo@codeaurora.org>
Cc:     Yan-Hsuan Chuang <yhchuang@realtek.com>
Subject: Re: [PATCH 5.1] rtw88: fix subscript above array bounds compiler
 warning
Message-ID: <20190506084221.GB2714@redhat.com>
References: <20190506073917.10106-1-sgruszka@redhat.com>
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This is for 5.2 and v2 obviously.

Stanislaw

On Mon, May 06, 2019 at 09:39:17AM +0200, Stanislaw Gruszka wrote:
> My compiler complains about:
> 
> drivers/net/wireless/realtek/rtw88/phy.c: In function ???rtw_phy_rf_power_2_rssi???:
> drivers/net/wireless/realtek/rtw88/phy.c:430:26: warning: array subscript is above array bounds [-Warray-bounds]
>   linear = db_invert_table[i][j];
> 
> According to comment power_db should be in range 1 ~ 96 .
> To fix add check for boundaries before access the array.
> 
> Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
> ---
> RFC -> v1
> - add check before accessing the array insted of
>   rtw_phy_power_2_db() change.
> v1 -> v2:
> - return 1 for power_db < 1
> 
>  drivers/net/wireless/realtek/rtw88/phy.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/net/wireless/realtek/rtw88/phy.c b/drivers/net/wireless/realtek/rtw88/phy.c
> index 4381b360b5b5..9ca52a4d025a 100644
> --- a/drivers/net/wireless/realtek/rtw88/phy.c
> +++ b/drivers/net/wireless/realtek/rtw88/phy.c
> @@ -423,6 +423,11 @@ static u64 rtw_phy_db_2_linear(u8 power_db)
>  	u8 i, j;
>  	u64 linear;
>  
> +	if (power_db > 96)
> +		power_db = 96;
> +	else if (power_db < 1)
> +		return 1;
> +
>  	/* 1dB ~ 96dB */
>  	i = (power_db - 1) >> 3;
>  	j = (power_db - 1) - (i << 3);
> -- 
> 2.20.1
>