* [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false
@ 2025-04-09 2:11 kernel test robot
2025-04-09 2:51 ` Guenter Roeck
0 siblings, 1 reply; 5+ messages in thread
From: kernel test robot @ 2025-04-09 2:11 UTC (permalink / raw)
To: Alexander Stein; +Cc: llvm, oe-kbuild-all, linux-hwmon, Guenter Roeck
tree: https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
head: d6b1492c9c2e7f2659b63a165ea45ab556c0df0c
commit: d6b1492c9c2e7f2659b63a165ea45ab556c0df0c [13/13] hwmon: (gpio-fan) Add regulator support
config: riscv-randconfig-001-20250409 (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/config)
compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 92c93f5286b9ff33f27ff694d2dc33da1c07afdd)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/reproduce)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202504091047.biuX8Kl2-lkp@intel.com/
All warnings (new ones prefixed by >>):
>> drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
250 | if (val == 0)
| ^~~~~~~~
drivers/hwmon/gpio-fan.c:255:9: note: uninitialized use occurs here
255 | return ret ? ret : count;
| ^~~
drivers/hwmon/gpio-fan.c:250:2: note: remove the 'if' if its condition is always true
250 | if (val == 0)
| ^~~~~~~~~~~~~
251 | ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
drivers/hwmon/gpio-fan.c:237:9: note: initialize the variable 'ret' to silence this warning
237 | int ret;
| ^
| = 0
1 warning generated.
vim +250 drivers/hwmon/gpio-fan.c
d6fe1360f42e86 Simon Guinot 2010-10-22 230
c490c63e9505a3 Julia Lawall 2016-12-22 231 static ssize_t pwm1_enable_store(struct device *dev,
c490c63e9505a3 Julia Lawall 2016-12-22 232 struct device_attribute *attr,
d6fe1360f42e86 Simon Guinot 2010-10-22 233 const char *buf, size_t count)
d6fe1360f42e86 Simon Guinot 2010-10-22 234 {
d6fe1360f42e86 Simon Guinot 2010-10-22 235 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
d6fe1360f42e86 Simon Guinot 2010-10-22 236 unsigned long val;
d6b1492c9c2e7f Alexander Stein 2025-04-08 237 int ret;
d6fe1360f42e86 Simon Guinot 2010-10-22 238
179c4fdb565dd2 Frans Meulenbroeks 2012-01-04 239 if (kstrtoul(buf, 10, &val) || val > 1)
d6fe1360f42e86 Simon Guinot 2010-10-22 240 return -EINVAL;
d6fe1360f42e86 Simon Guinot 2010-10-22 241
d6fe1360f42e86 Simon Guinot 2010-10-22 242 if (fan_data->pwm_enable == val)
d6fe1360f42e86 Simon Guinot 2010-10-22 243 return count;
d6fe1360f42e86 Simon Guinot 2010-10-22 244
d6fe1360f42e86 Simon Guinot 2010-10-22 245 mutex_lock(&fan_data->lock);
d6fe1360f42e86 Simon Guinot 2010-10-22 246
d6fe1360f42e86 Simon Guinot 2010-10-22 247 fan_data->pwm_enable = val;
d6fe1360f42e86 Simon Guinot 2010-10-22 248
d6fe1360f42e86 Simon Guinot 2010-10-22 249 /* Disable manual control mode: set fan at full speed. */
d6fe1360f42e86 Simon Guinot 2010-10-22 @250 if (val == 0)
d6b1492c9c2e7f Alexander Stein 2025-04-08 251 ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
d6fe1360f42e86 Simon Guinot 2010-10-22 252
d6fe1360f42e86 Simon Guinot 2010-10-22 253 mutex_unlock(&fan_data->lock);
d6fe1360f42e86 Simon Guinot 2010-10-22 254
d6b1492c9c2e7f Alexander Stein 2025-04-08 255 return ret ? ret : count;
d6fe1360f42e86 Simon Guinot 2010-10-22 256 }
d6fe1360f42e86 Simon Guinot 2010-10-22 257
:::::: The code at line 250 was first introduced by commit
:::::: d6fe1360f42e86262153927986dea6502daff703 hwmon: add generic GPIO fan driver
:::::: TO: Simon Guinot <sguinot@lacie.com>
:::::: CC: Guenter Roeck <guenter.roeck@ericsson.com>
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false
2025-04-09 2:11 [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false kernel test robot
@ 2025-04-09 2:51 ` Guenter Roeck
2025-04-09 6:50 ` Alexander Stein
0 siblings, 1 reply; 5+ messages in thread
From: Guenter Roeck @ 2025-04-09 2:51 UTC (permalink / raw)
To: kernel test robot, Alexander Stein; +Cc: llvm, oe-kbuild-all, linux-hwmon
Alexander,
On 4/8/25 19:11, kernel test robot wrote:
> tree: https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
> head: d6b1492c9c2e7f2659b63a165ea45ab556c0df0c
> commit: d6b1492c9c2e7f2659b63a165ea45ab556c0df0c [13/13] hwmon: (gpio-fan) Add regulator support
> config: riscv-randconfig-001-20250409 (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/config)
> compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 92c93f5286b9ff33f27ff694d2dc33da1c07afdd)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/reproduce)
>
> If you fix the issue in a separate patch/commit (i.e. not just a new version of
> the same patch/commit), kindly add following tags
> | Reported-by: kernel test robot <lkp@intel.com>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202504091047.biuX8Kl2-lkp@intel.com/
>
> All warnings (new ones prefixed by >>):
>
>>> drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
> 250 | if (val == 0)
> | ^~~~~~~~
> drivers/hwmon/gpio-fan.c:255:9: note: uninitialized use occurs here
> 255 | return ret ? ret : count;
> | ^~~
> drivers/hwmon/gpio-fan.c:250:2: note: remove the 'if' if its condition is always true
> 250 | if (val == 0)
> | ^~~~~~~~~~~~~
> 251 | ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
> drivers/hwmon/gpio-fan.c:237:9: note: initialize the variable 'ret' to silence this warning
> 237 | int ret;
> | ^
> | = 0
> 1 warning generated.
>
I dropped the patch from linux-next. Please fix and make sure there are no
such problems before resubmitting.
Thanks,
Guenter
>
> vim +250 drivers/hwmon/gpio-fan.c
>
> d6fe1360f42e86 Simon Guinot 2010-10-22 230
> c490c63e9505a3 Julia Lawall 2016-12-22 231 static ssize_t pwm1_enable_store(struct device *dev,
> c490c63e9505a3 Julia Lawall 2016-12-22 232 struct device_attribute *attr,
> d6fe1360f42e86 Simon Guinot 2010-10-22 233 const char *buf, size_t count)
> d6fe1360f42e86 Simon Guinot 2010-10-22 234 {
> d6fe1360f42e86 Simon Guinot 2010-10-22 235 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
> d6fe1360f42e86 Simon Guinot 2010-10-22 236 unsigned long val;
> d6b1492c9c2e7f Alexander Stein 2025-04-08 237 int ret;
> d6fe1360f42e86 Simon Guinot 2010-10-22 238
> 179c4fdb565dd2 Frans Meulenbroeks 2012-01-04 239 if (kstrtoul(buf, 10, &val) || val > 1)
> d6fe1360f42e86 Simon Guinot 2010-10-22 240 return -EINVAL;
> d6fe1360f42e86 Simon Guinot 2010-10-22 241
> d6fe1360f42e86 Simon Guinot 2010-10-22 242 if (fan_data->pwm_enable == val)
> d6fe1360f42e86 Simon Guinot 2010-10-22 243 return count;
> d6fe1360f42e86 Simon Guinot 2010-10-22 244
> d6fe1360f42e86 Simon Guinot 2010-10-22 245 mutex_lock(&fan_data->lock);
> d6fe1360f42e86 Simon Guinot 2010-10-22 246
> d6fe1360f42e86 Simon Guinot 2010-10-22 247 fan_data->pwm_enable = val;
> d6fe1360f42e86 Simon Guinot 2010-10-22 248
> d6fe1360f42e86 Simon Guinot 2010-10-22 249 /* Disable manual control mode: set fan at full speed. */
> d6fe1360f42e86 Simon Guinot 2010-10-22 @250 if (val == 0)
> d6b1492c9c2e7f Alexander Stein 2025-04-08 251 ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
> d6fe1360f42e86 Simon Guinot 2010-10-22 252
> d6fe1360f42e86 Simon Guinot 2010-10-22 253 mutex_unlock(&fan_data->lock);
> d6fe1360f42e86 Simon Guinot 2010-10-22 254
> d6b1492c9c2e7f Alexander Stein 2025-04-08 255 return ret ? ret : count;
> d6fe1360f42e86 Simon Guinot 2010-10-22 256 }
> d6fe1360f42e86 Simon Guinot 2010-10-22 257
>
> :::::: The code at line 250 was first introduced by commit
> :::::: d6fe1360f42e86262153927986dea6502daff703 hwmon: add generic GPIO fan driver
>
> :::::: TO: Simon Guinot <sguinot@lacie.com>
> :::::: CC: Guenter Roeck <guenter.roeck@ericsson.com>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false
2025-04-09 2:51 ` Guenter Roeck
@ 2025-04-09 6:50 ` Alexander Stein
2025-04-09 16:02 ` Nathan Chancellor
0 siblings, 1 reply; 5+ messages in thread
From: Alexander Stein @ 2025-04-09 6:50 UTC (permalink / raw)
To: kernel test robot, Guenter Roeck; +Cc: llvm, oe-kbuild-all, linux-hwmon
Hi Guenter,
Am Mittwoch, 9. April 2025, 04:51:35 CEST schrieb Guenter Roeck:
> Alexander,
>
> On 4/8/25 19:11, kernel test robot wrote:
> > tree: https://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging.git hwmon-next
> > head: d6b1492c9c2e7f2659b63a165ea45ab556c0df0c
> > commit: d6b1492c9c2e7f2659b63a165ea45ab556c0df0c [13/13] hwmon: (gpio-fan) Add regulator support
> > config: riscv-randconfig-001-20250409 (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/config)
> > compiler: clang version 21.0.0git (https://github.com/llvm/llvm-project 92c93f5286b9ff33f27ff694d2dc33da1c07afdd)
> > reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250409/202504091047.biuX8Kl2-lkp@intel.com/reproduce)
> >
> > If you fix the issue in a separate patch/commit (i.e. not just a new version of
> > the same patch/commit), kindly add following tags
> > | Reported-by: kernel test robot <lkp@intel.com>
> > | Closes: https://lore.kernel.org/oe-kbuild-all/202504091047.biuX8Kl2-lkp@intel.com/
> >
> > All warnings (new ones prefixed by >>):
> >
> >>> drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
> > 250 | if (val == 0)
> > | ^~~~~~~~
> > drivers/hwmon/gpio-fan.c:255:9: note: uninitialized use occurs here
> > 255 | return ret ? ret : count;
> > | ^~~
> > drivers/hwmon/gpio-fan.c:250:2: note: remove the 'if' if its condition is always true
> > 250 | if (val == 0)
> > | ^~~~~~~~~~~~~
> > 251 | ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
> > drivers/hwmon/gpio-fan.c:237:9: note: initialize the variable 'ret' to silence this warning
> > 237 | int ret;
> > | ^
> > | = 0
> > 1 warning generated.
> >
>
> I dropped the patch from linux-next. Please fix and make sure there are no
> such problems before resubmitting.
Oh, surprising. A W=1 build on my machine doesn't raise this warning. I'm not
sure if this is specific to riscv or clang. Nevertheless this is correct and
I'll send a fixed one.
Thanks and best regards
Alexander
> Thanks,
> Guenter
> >
> > vim +250 drivers/hwmon/gpio-fan.c
> >
> > d6fe1360f42e86 Simon Guinot 2010-10-22 230
> > c490c63e9505a3 Julia Lawall 2016-12-22 231 static ssize_t pwm1_enable_store(struct device *dev,
> > c490c63e9505a3 Julia Lawall 2016-12-22 232 struct device_attribute *attr,
> > d6fe1360f42e86 Simon Guinot 2010-10-22 233 const char *buf, size_t count)
> > d6fe1360f42e86 Simon Guinot 2010-10-22 234 {
> > d6fe1360f42e86 Simon Guinot 2010-10-22 235 struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
> > d6fe1360f42e86 Simon Guinot 2010-10-22 236 unsigned long val;
> > d6b1492c9c2e7f Alexander Stein 2025-04-08 237 int ret;
> > d6fe1360f42e86 Simon Guinot 2010-10-22 238
> > 179c4fdb565dd2 Frans Meulenbroeks 2012-01-04 239 if (kstrtoul(buf, 10, &val) || val > 1)
> > d6fe1360f42e86 Simon Guinot 2010-10-22 240 return -EINVAL;
> > d6fe1360f42e86 Simon Guinot 2010-10-22 241
> > d6fe1360f42e86 Simon Guinot 2010-10-22 242 if (fan_data->pwm_enable == val)
> > d6fe1360f42e86 Simon Guinot 2010-10-22 243 return count;
> > d6fe1360f42e86 Simon Guinot 2010-10-22 244
> > d6fe1360f42e86 Simon Guinot 2010-10-22 245 mutex_lock(&fan_data->lock);
> > d6fe1360f42e86 Simon Guinot 2010-10-22 246
> > d6fe1360f42e86 Simon Guinot 2010-10-22 247 fan_data->pwm_enable = val;
> > d6fe1360f42e86 Simon Guinot 2010-10-22 248
> > d6fe1360f42e86 Simon Guinot 2010-10-22 249 /* Disable manual control mode: set fan at full speed. */
> > d6fe1360f42e86 Simon Guinot 2010-10-22 @250 if (val == 0)
> > d6b1492c9c2e7f Alexander Stein 2025-04-08 251 ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
> > d6fe1360f42e86 Simon Guinot 2010-10-22 252
> > d6fe1360f42e86 Simon Guinot 2010-10-22 253 mutex_unlock(&fan_data->lock);
> > d6fe1360f42e86 Simon Guinot 2010-10-22 254
> > d6b1492c9c2e7f Alexander Stein 2025-04-08 255 return ret ? ret : count;
> > d6fe1360f42e86 Simon Guinot 2010-10-22 256 }
> > d6fe1360f42e86 Simon Guinot 2010-10-22 257
> >
> > :::::: The code at line 250 was first introduced by commit
> > :::::: d6fe1360f42e86262153927986dea6502daff703 hwmon: add generic GPIO fan driver
> >
> > :::::: TO: Simon Guinot <sguinot@lacie.com>
> > :::::: CC: Guenter Roeck <guenter.roeck@ericsson.com>
> >
>
>
--
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
http://www.tq-group.com/
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false
2025-04-09 6:50 ` Alexander Stein
@ 2025-04-09 16:02 ` Nathan Chancellor
2025-04-10 8:35 ` Dan Carpenter
0 siblings, 1 reply; 5+ messages in thread
From: Nathan Chancellor @ 2025-04-09 16:02 UTC (permalink / raw)
To: Alexander Stein
Cc: kernel test robot, Guenter Roeck, llvm, oe-kbuild-all,
linux-hwmon
On Wed, Apr 09, 2025 at 08:50:14AM +0200, Alexander Stein wrote:
> Am Mittwoch, 9. April 2025, 04:51:35 CEST schrieb Guenter Roeck:
> > On 4/8/25 19:11, kernel test robot wrote:
> > > All warnings (new ones prefixed by >>):
> > >
> > >>> drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
> > > 250 | if (val == 0)
> > > | ^~~~~~~~
> > > drivers/hwmon/gpio-fan.c:255:9: note: uninitialized use occurs here
> > > 255 | return ret ? ret : count;
> > > | ^~~
> > > drivers/hwmon/gpio-fan.c:250:2: note: remove the 'if' if its condition is always true
> > > 250 | if (val == 0)
> > > | ^~~~~~~~~~~~~
> > > 251 | ret = set_fan_speed(fan_data, fan_data->num_speed - 1);
> > > drivers/hwmon/gpio-fan.c:237:9: note: initialize the variable 'ret' to silence this warning
> > > 237 | int ret;
> > > | ^
> > > | = 0
> > > 1 warning generated.
> > >
> >
> > I dropped the patch from linux-next. Please fix and make sure there are no
> > such problems before resubmitting.
>
> Oh, surprising. A W=1 build on my machine doesn't raise this warning. I'm not
> sure if this is specific to riscv or clang. Nevertheless this is correct and
> I'll send a fixed one.
Unfortunately, the kernel disabled GCC's version, -Wmaybe-uninitialized,
several years ago in commit 78a5255ffb6a ("Stop the ad-hoc games with
-Wno-maybe-initialized"), so you either need to add it yourself via
KCFLAGS or just do a quick pass with Clang's slightly weaker but more
reliable -Wsometimes-uninitialized. I have fast versions of clang
available on kernel.org to make doing this testing a little easier:
https://mirrors.edge.kernel.org/pub/tools/llvm/
Cheers,
Nathan
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false
2025-04-09 16:02 ` Nathan Chancellor
@ 2025-04-10 8:35 ` Dan Carpenter
0 siblings, 0 replies; 5+ messages in thread
From: Dan Carpenter @ 2025-04-10 8:35 UTC (permalink / raw)
To: Nathan Chancellor
Cc: Alexander Stein, kernel test robot, Guenter Roeck, llvm,
oe-kbuild-all, linux-hwmon
Another option is Smatch.
https://github.com/error27/smatch
:! ~/progs/smatch/release/smatch_scripts/kchecker drivers/hwmon/gpio-fan.c
CHECK scripts/mod/empty.c
CALL scripts/checksyscalls.sh
DESCEND objtool
INSTALL libsubcmd_headers
CC drivers/hwmon/gpio-fan.o
CHECK drivers/hwmon/gpio-fan.c
drivers/hwmon/gpio-fan.c:145 set_fan_speed() warn: potential spectre issue 'fan_data->speed' [w] (local cap)
drivers/hwmon/gpio-fan.c:255 pwm1_enable_store() error: uninitialized symbol 'ret'.
I don't think the spectre v1 issue is real but I don't know very much
about spectre.
regards,
dan carpenter
^ permalink raw reply [flat|nested] 5+ messages in thread
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2025-04-09 2:11 [groeck-staging:hwmon-next 13/13] drivers/hwmon/gpio-fan.c:250:6: warning: variable 'ret' is used uninitialized whenever 'if' condition is false kernel test robot
2025-04-09 2:51 ` Guenter Roeck
2025-04-09 6:50 ` Alexander Stein
2025-04-09 16:02 ` Nathan Chancellor
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