2022-07-27 10:03:46

by Alexandre Belloni

Subject: [PATCH] rtc: zynqmp: initialize fract_tick

From: Alexandre Belloni <[email protected]>

fract_tick is used uninitialized when fract_offset is 0

Reported-by: kernel test robot <[email protected]>
Signed-off-by: Alexandre Belloni <[email protected]>
---
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;
--
2.36.1

2022-07-27 10:59:28

by Michal Simek

Subject: Re: [PATCH] rtc: zynqmp: initialize fract_tick

On 7/27/22 12:00, [email protected] wrote:
> From: Alexandre Belloni <[email protected]>
>
> fract_tick is used uninitialized when fract_offset is 0
>
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Alexandre Belloni <[email protected]>
> ---
> 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;
> --
> 2.36.1
>

Reviewed-by: Michal Simek <[email protected]>

Thanks,
Michal

2022-08-05 17:14:42

by Nathan Chancellor

Subject: Re: [PATCH] rtc: zynqmp: initialize fract_tick

On Wed, Jul 27, 2022 at 12:00:18PM +0200, [email protected] wrote:
> From: Alexandre Belloni <[email protected]>
>
> fract_tick is used uninitialized when fract_offset is 0
>
> Reported-by: kernel test robot <[email protected]>
> Signed-off-by: Alexandre Belloni <[email protected]>

Reviewed-by: Nathan Chancellor <[email protected]>

Is this going to be applied soon? This is one of the warnings breaking
allmodconfig with clang right now:

drivers/rtc/rtc-zynqmp.c:223:7: error: variable 'fract_tick' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/rtc/rtc-zynqmp.c:238:6: note: uninitialized use occurs here
if (fract_tick)
^~~~~~~~~~
drivers/rtc/rtc-zynqmp.c:223:3: note: remove the 'if' if its condition is always true
if (fract_offset > (tick_mult / RTC_FR_MAX_TICKS)) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/rtc/rtc-zynqmp.c:218:6: error: variable 'fract_tick' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
if (fract_offset) {
^~~~~~~~~~~~
drivers/rtc/rtc-zynqmp.c:238:6: note: uninitialized use occurs here
if (fract_tick)
^~~~~~~~~~
drivers/rtc/rtc-zynqmp.c:218:2: note: remove the 'if' if its condition is always true
if (fract_offset) {
^~~~~~~~~~~~~~~~~~
drivers/rtc/rtc-zynqmp.c:206:26: note: initialize the variable 'fract_tick' to silence this warning
unsigned char fract_tick;
^
= '\0'
2 errors generated.

> ---
> 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;
> --
> 2.36.1
>
>