[lvc-project] [PATCH] ssb-main: Fix division by zero in ssb_calc_clock_rate()

[Alexey Khoroshilov]

Dear Rand,

1. It seems you have incorrect list of recipients, please, use
get_maintainers.pl to get correct one.

On 29.08.2023 14:12, Rand Deeb wrote:
> In the line 910, the value of m1 may be zero, so there is a possibility
> of dividing by zero, we fixed it by checking the values before dividing
> (found with SVACE). In the same way, after checking and reading the
> function, we found that lines 906, 908, 912 have the same situation, so
> we fixed them as well.

2. It would be good to justify why zero can happen here.
3. It is not recommended to use line numbers in commit messages.
4. As for the patch, it does not have else branches and at leaset break
statement should be added.

--
Alexey


> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Signed-off-by: Rand Deeb <deeb.rand at confident.ru>
> ---
>  drivers/ssb/main.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ssb/main.c b/drivers/ssb/main.c
> index 0a26984acb2c..e0776a16d04d 100644
> --- a/drivers/ssb/main.c
> +++ b/drivers/ssb/main.c
> @@ -903,13 +903,21 @@ u32 ssb_calc_clock_rate(u32 plltype, u32 n, u32 m)
>  		case SSB_CHIPCO_CLK_MC_BYPASS:
>  			return clock;
>  		case SSB_CHIPCO_CLK_MC_M1:
> -			return (clock / m1);
> +			if (m1 != 0)
> +				return (clock / m1);
> +			break;
>  		case SSB_CHIPCO_CLK_MC_M1M2:
> -			return (clock / (m1 * m2));
> +			if ((m1 * m2) != 0)
> +				return (clock / (m1 * m2));
> +			break;
>  		case SSB_CHIPCO_CLK_MC_M1M2M3:
> -			return (clock / (m1 * m2 * m3));
> +			if ((m1 * m2 * m3) != 0)
> +				return (clock / (m1 * m2 * m3));
> +			break;
>  		case SSB_CHIPCO_CLK_MC_M1M3:
> -			return (clock / (m1 * m3));
> +			if ((m1 * m3) != 0)
> +				return (clock / (m1 * m3));
> +			break;
>  		}
>  		return 0;
>  	case SSB_PLLTYPE_2:
>