[Linux-stm32] [PATCH] i2c: stm32f7: prevent array underflow in stm32f7_get_lower_rate()

[Alain Volmat]

Hi Dan,

indeed, thanks a lot.

Reviewed-by: Alain Volmat <alain.volmat at st.com>

Alain

On Wed, Apr 29, 2020 at 04:23:23PM +0300, Dan Carpenter wrote:
> We want to break with "i" set to zero whether we find the rate we want
> or not.  In the current code, if we don't find the rate we want then it
> exits the loop with "i" set to -1 and results in an array underflow.
> 
> Fixes: 09cc9a3bce91 ("i2c: stm32f7: allows for any bus frequency")
> Signed-off-by: Dan Carpenter <dan.carpenter at oracle.com>
> ---
>  drivers/i2c/busses/i2c-stm32f7.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/i2c/busses/i2c-stm32f7.c b/drivers/i2c/busses/i2c-stm32f7.c
> index 9c9e10ea91991..bff3479fe122a 100644
> --- a/drivers/i2c/busses/i2c-stm32f7.c
> +++ b/drivers/i2c/busses/i2c-stm32f7.c
> @@ -607,7 +607,7 @@ static u32 stm32f7_get_lower_rate(u32 rate)
>  {
>  	int i = ARRAY_SIZE(stm32f7_i2c_specs);
>  
> -	while (i--)
> +	while (--i)
>  		if (stm32f7_i2c_specs[i].rate < rate)
>  			break;
>  
> -- 
> 2.26.2
>