diff mbox series

[v2,2/4] platform/x86: int3472: Simplify dev_err_probe() usage

Message ID 20240822130722.1261891-3-andriy.shevchenko@linux.intel.com (mailing list archive)
State Rejected, archived
Headers show
Series platform/x86: int3472: A few cleanups | expand

Commit Message

Andy Shevchenko Aug. 22, 2024, 1:05 p.m. UTC 
Since dev_err_probe() ignores success, i.e. 0. we may call
it unconditionally.

Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/platform/x86/intel/int3472/discrete.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

Comments

Dan Carpenter Aug. 31, 2024, 8:31 a.m. UTC | #1 
Hi Andy,

kernel test robot noticed the following build warnings:

https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/driver-core-Ignore-0-in-dev_err_probe/20240826-113856
base:   driver-core/driver-core-testing
patch link:    https://lore.kernel.org/r/20240822130722.1261891-3-andriy.shevchenko%40linux.intel.com
patch subject: [PATCH v2 2/4] platform/x86: int3472: Simplify dev_err_probe() usage
config: i386-randconfig-141-20240830 (https://download.01.org/0day-ci/archive/20240831/202408310807.sNPe5Mr2-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0

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>
| Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
| Closes: https://lore.kernel.org/r/202408310807.sNPe5Mr2-lkp@intel.com/

smatch warnings:
drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() error: uninitialized symbol 'err_msg'.
drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() warn: passing zero to 'dev_err_probe'

vim +/err_msg +292 drivers/platform/x86/intel/int3472/discrete.c

5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  270  		case INT3472_GPIO_TYPE_POWER_ENABLE:
53c5f7f6e7930f drivers/platform/x86/intel/int3472/discrete.c                   Hans de Goede   2023-10-04  271  			ret = skl_int3472_register_regulator(int3472, gpio);
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  272  			if (ret)
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  273  				err_msg = "Failed to map regulator to sensor\n";
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  274  
53c5f7f6e7930f drivers/platform/x86/intel/int3472/discrete.c                   Hans de Goede   2023-10-04  275  			break;
53c5f7f6e7930f drivers/platform/x86/intel/int3472/discrete.c                   Hans de Goede   2023-10-04  276  		default: /* Never reached */
53c5f7f6e7930f drivers/platform/x86/intel/int3472/discrete.c                   Hans de Goede   2023-10-04  277  			ret = -EINVAL;
53c5f7f6e7930f drivers/platform/x86/intel/int3472/discrete.c                   Hans de Goede   2023-10-04  278  			break;
53c5f7f6e7930f drivers/platform/x86/intel/int3472/discrete.c                   Hans de Goede   2023-10-04  279  		}
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  280  		break;
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  281  	default:
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  282  		dev_warn(int3472->dev,
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  283  			 "GPIO type 0x%02x unknown; the sensor may not work\n",
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  284  			 type);
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  285  		ret = 1;
                                                                                                                                ^^^^^^^^

5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  286  		break;
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  287  	}
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  288  
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  289  	int3472->ngpios++;
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  290  	ACPI_FREE(obj);
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03  291  
5de691bffe57fd drivers/platform/x86/intel-int3472/intel_skl_int3472_discrete.c Daniel Scally   2021-06-03 @292  	return dev_err_probe(int3472->dev, ret, err_msg);

This is the success path.  "err_msg" is only set for the error path.  "ret" is 1
so it will use the uninitialized data.  But even if ret were zero, it's illegal
to pass uninitialized variables to functions which aren't inlined.

1) It's undefined behavior
2) Linus said so
3) It causes UBSan warnings at runtime.

regards,
dan carpenter
Andy Shevchenko Sept. 2, 2024, 10:17 a.m. UTC | #2 
On Sat, Aug 31, 2024 at 11:31:53AM +0300, Dan Carpenter wrote:
> Hi Andy,
> 
> kernel test robot noticed the following build warnings:
> 
> https://git-scm.com/docs/git-format-patch#_base_tree_information]
> 
> url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/driver-core-Ignore-0-in-dev_err_probe/20240826-113856
> base:   driver-core/driver-core-testing
> patch link:    https://lore.kernel.org/r/20240822130722.1261891-3-andriy.shevchenko%40linux.intel.com
> patch subject: [PATCH v2 2/4] platform/x86: int3472: Simplify dev_err_probe() usage
> config: i386-randconfig-141-20240830 (https://download.01.org/0day-ci/archive/20240831/202408310807.sNPe5Mr2-lkp@intel.com/config)
> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> 
> 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>
> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> | Closes: https://lore.kernel.org/r/202408310807.sNPe5Mr2-lkp@intel.com/
> 
> smatch warnings:
> drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() error: uninitialized symbol 'err_msg'.
> drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() warn: passing zero to 'dev_err_probe'

Okay, I might agree on the err_msg, which is good to have to be passed anyway.
In such a case it might be good to have a dev_dbg() in the dev_err_probe() to
say that it is likely a bug in the code.

Would you accept that approach?
Dan Carpenter Sept. 2, 2024, 11:23 a.m. UTC | #3 
On Mon, Sep 02, 2024 at 01:17:51PM +0300, Andy Shevchenko wrote:
> On Sat, Aug 31, 2024 at 11:31:53AM +0300, Dan Carpenter wrote:
> > Hi Andy,
> > 
> > kernel test robot noticed the following build warnings:
> > 
> > https://git-scm.com/docs/git-format-patch#_base_tree_information]
> > 
> > url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/driver-core-Ignore-0-in-dev_err_probe/20240826-113856
> > base:   driver-core/driver-core-testing
> > patch link:    https://lore.kernel.org/r/20240822130722.1261891-3-andriy.shevchenko%40linux.intel.com
> > patch subject: [PATCH v2 2/4] platform/x86: int3472: Simplify dev_err_probe() usage
> > config: i386-randconfig-141-20240830 (https://download.01.org/0day-ci/archive/20240831/202408310807.sNPe5Mr2-lkp@intel.com/config)
> > compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
> > 
> > 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>
> > | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
> > | Closes: https://lore.kernel.org/r/202408310807.sNPe5Mr2-lkp@intel.com/
> > 
> > smatch warnings:
> > drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() error: uninitialized symbol 'err_msg'.
> > drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() warn: passing zero to 'dev_err_probe'
> 
> Okay, I might agree on the err_msg, which is good to have to be passed anyway.
> In such a case it might be good to have a dev_dbg() in the dev_err_probe() to
> say that it is likely a bug in the code.
> 
> Would you accept that approach?

ret is 1.  We have to revert this patch.

regards,
dan carpenter
Hans de Goede Sept. 2, 2024, 11:32 a.m. UTC | #4 
Hi,

On 9/2/24 1:23 PM, Dan Carpenter wrote:
> On Mon, Sep 02, 2024 at 01:17:51PM +0300, Andy Shevchenko wrote:
>> On Sat, Aug 31, 2024 at 11:31:53AM +0300, Dan Carpenter wrote:
>>> Hi Andy,
>>>
>>> kernel test robot noticed the following build warnings:
>>>
>>> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>>>
>>> url:    https://github.com/intel-lab-lkp/linux/commits/Andy-Shevchenko/driver-core-Ignore-0-in-dev_err_probe/20240826-113856
>>> base:   driver-core/driver-core-testing
>>> patch link:    https://lore.kernel.org/r/20240822130722.1261891-3-andriy.shevchenko%40linux.intel.com
>>> patch subject: [PATCH v2 2/4] platform/x86: int3472: Simplify dev_err_probe() usage
>>> config: i386-randconfig-141-20240830 (https://download.01.org/0day-ci/archive/20240831/202408310807.sNPe5Mr2-lkp@intel.com/config)
>>> compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
>>>
>>> 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>
>>> | Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
>>> | Closes: https://lore.kernel.org/r/202408310807.sNPe5Mr2-lkp@intel.com/
>>>
>>> smatch warnings:
>>> drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() error: uninitialized symbol 'err_msg'.
>>> drivers/platform/x86/intel/int3472/discrete.c:292 skl_int3472_handle_gpio_resources() warn: passing zero to 'dev_err_probe'
>>
>> Okay, I might agree on the err_msg, which is good to have to be passed anyway.
>> In such a case it might be good to have a dev_dbg() in the dev_err_probe() to
>> say that it is likely a bug in the code.
>>
>> Would you accept that approach?
> 
> ret is 1.  We have to revert this patch.

Note this was never applied, so no need to revert.

I'll apply patch 3/4 when I get around to it.

If some agreement is reached on patch 1/2 the new version of those can
be applied later.

Regards,

Hans
diff mbox series

Patch

diff --git a/drivers/platform/x86/intel/int3472/discrete.c b/drivers/platform/x86/intel/int3472/discrete.c
index 34db7d0381fd..29df19379464 100644
--- a/drivers/platform/x86/intel/int3472/discrete.c
+++ b/drivers/platform/x86/intel/int3472/discrete.c
@@ -299,10 +299,7 @@  static int skl_int3472_handle_gpio_resources(struct acpi_resource *ares,
 	int3472->ngpios++;
 	ACPI_FREE(obj);
 
-	if (ret < 0)
-		return dev_err_probe(int3472->dev, ret, err_msg);
-
-	return ret;
+	return dev_err_probe(int3472->dev, ret, err_msg);
 }
 
 static int skl_int3472_parse_crs(struct int3472_discrete_device *int3472)