Re: [PATCH -next] rtc: synqmp: uninitialized variable error

[Michal Simek]

Hi,

On 8/3/22 03:31, Sebin Sebastian wrote:
> fract_tick is uninitialized and can lead to uninitialized read which can
> result in any arbitrary value from previous computations. If the code
> flow doesnt execute the `if (fract_offset > (tick_mult /
> RTC_FR_MAX_TICKS)) { ` block, fract_tick is left uninitialized.
> Initializing with zero fixes the issue.
>
> Signed-off-by: Sebin Sebastian <mailmesebin00@xxxxxxxxx>
> ---
>   drivers/rtc/rtc-zynqmp.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/rtc/rtc-zynqmp.c b/drivers/rtc/rtc-zynqmp.c
> index 1dd389b891fe..c9b85c838ebe 100644
> --- a/drivers/rtc/rtc-zynqmp.c
> +++ b/drivers/rtc/rtc-zynqmp.c
> @@ -203,7 +203,7 @@ static int xlnx_rtc_set_offset(struct device *dev, long offset)
>          struct xlnx_rtc_dev *xrtcdev = dev_get_drvdata(dev);
>          unsigned long long rtc_ppb = RTC_PPB;
>          unsigned int tick_mult = do_div(rtc_ppb, xrtcdev->freq);
> -       unsigned char fract_tick;
> +       unsigned char fract_tick = 0;
>          unsigned int calibval;
>          short int  max_tick;
>          int fract_offset;
> --
> 2.34.1

Alexandre already send the patch for it here.

https://lore.kernel.org/r/20220727100018.3301470-1-alexandre.belloni@xxxxxxxxxxx

Thanks,
Michal