Re: [PATCH] intel_th: Fix error handling in intel_th_output_open

Re: [PATCH] intel_th: Fix error handling in intel_th_output_open

[kernel test robot]

Hi Ma,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master v6.18-rc5 next-20251111]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ma-Ke/intel_th-Fix-error-handling-in-intel_th_output_open/20251111-104412
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20251111024204.12299-1-make24%40iscas.ac.cn
patch subject: [PATCH] intel_th: Fix error handling in intel_th_output_open
config: x86_64-buildonly-randconfig-002-20251111 (https://download.01.org/0day-ci/archive/20251111/202511112222.vMmKmHbd-lkp@intel.com/config)
compiler: clang version 20.1.8 (https://github.com/llvm/llvm-project 87f0227cb60147a26a1eeb4fb06e3b505e9c7261)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20251111/202511112222.vMmKmHbd-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/202511112222.vMmKmHbd-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/hwtracing/intel_th/core.c:818:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
     818 |         if (!fops)
         |             ^~~~~
   drivers/hwtracing/intel_th/core.c:836:9: note: uninitialized use occurs here
     836 |         return err;
         |                ^~~
   drivers/hwtracing/intel_th/core.c:818:2: note: remove the 'if' if its condition is always false
     818 |         if (!fops)
         |         ^~~~~~~~~~
     819 |                 goto out_put_device;
         |                 ~~~~~~~~~~~~~~~~~~~
   drivers/hwtracing/intel_th/core.c:813:6: warning: variable 'err' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
     813 |         if (!dev || !dev->driver)
         |             ^~~~~~~~~~~~~~~~~~~~
   drivers/hwtracing/intel_th/core.c:836:9: note: uninitialized use occurs here
     836 |         return err;
         |                ^~~
   drivers/hwtracing/intel_th/core.c:813:2: note: remove the 'if' if its condition is always false
     813 |         if (!dev || !dev->driver)
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~
     814 |                 goto out_no_device;
         |                 ~~~~~~~~~~~~~~~~~~
>> drivers/hwtracing/intel_th/core.c:813:6: warning: variable 'err' is used uninitialized whenever '||' condition is true [-Wsometimes-uninitialized]
     813 |         if (!dev || !dev->driver)
         |             ^~~~
   drivers/hwtracing/intel_th/core.c:836:9: note: uninitialized use occurs here
     836 |         return err;
         |                ^~~
   drivers/hwtracing/intel_th/core.c:813:6: note: remove the '||' if its condition is always false
     813 |         if (!dev || !dev->driver)
         |             ^~~~~~~
   drivers/hwtracing/intel_th/core.c:810:9: note: initialize the variable 'err' to silence this warning
     810 |         int err;
         |                ^
         |                 = 0
   3 warnings generated.


vim +818 drivers/hwtracing/intel_th/core.c

39f4034693b7c7 Alexander Shishkin 2015-09-22  804  
39f4034693b7c7 Alexander Shishkin 2015-09-22  805  static int intel_th_output_open(struct inode *inode, struct file *file)
39f4034693b7c7 Alexander Shishkin 2015-09-22  806  {
39f4034693b7c7 Alexander Shishkin 2015-09-22  807  	const struct file_operations *fops;
39f4034693b7c7 Alexander Shishkin 2015-09-22  808  	struct intel_th_driver *thdrv;
39f4034693b7c7 Alexander Shishkin 2015-09-22  809  	struct device *dev;
39f4034693b7c7 Alexander Shishkin 2015-09-22  810  	int err;
39f4034693b7c7 Alexander Shishkin 2015-09-22  811  
4495dfdd6193d9 Suzuki K Poulose   2019-07-23  812  	dev = bus_find_device_by_devt(&intel_th_bus, inode->i_rdev);
39f4034693b7c7 Alexander Shishkin 2015-09-22 @813  	if (!dev || !dev->driver)
b54f5a424fbe0f Ma Ke              2025-11-11  814  		goto out_no_device;
39f4034693b7c7 Alexander Shishkin 2015-09-22  815  
39f4034693b7c7 Alexander Shishkin 2015-09-22  816  	thdrv = to_intel_th_driver(dev->driver);
39f4034693b7c7 Alexander Shishkin 2015-09-22  817  	fops = fops_get(thdrv->fops);
39f4034693b7c7 Alexander Shishkin 2015-09-22 @818  	if (!fops)
b54f5a424fbe0f Ma Ke              2025-11-11  819  		goto out_put_device;
39f4034693b7c7 Alexander Shishkin 2015-09-22  820  
39f4034693b7c7 Alexander Shishkin 2015-09-22  821  	replace_fops(file, fops);
39f4034693b7c7 Alexander Shishkin 2015-09-22  822  
39f4034693b7c7 Alexander Shishkin 2015-09-22  823  	file->private_data = to_intel_th_device(dev);
39f4034693b7c7 Alexander Shishkin 2015-09-22  824  
39f4034693b7c7 Alexander Shishkin 2015-09-22  825  	if (file->f_op->open) {
39f4034693b7c7 Alexander Shishkin 2015-09-22  826  		err = file->f_op->open(inode, file);
b54f5a424fbe0f Ma Ke              2025-11-11  827  		if (err)
b54f5a424fbe0f Ma Ke              2025-11-11  828  			goto out_put_device;
39f4034693b7c7 Alexander Shishkin 2015-09-22  829  	}
39f4034693b7c7 Alexander Shishkin 2015-09-22  830  
39f4034693b7c7 Alexander Shishkin 2015-09-22  831  	return 0;
b54f5a424fbe0f Ma Ke              2025-11-11  832  
b54f5a424fbe0f Ma Ke              2025-11-11  833  out_put_device:
b54f5a424fbe0f Ma Ke              2025-11-11  834  	put_device(dev);
b54f5a424fbe0f Ma Ke              2025-11-11  835  out_no_device:
b54f5a424fbe0f Ma Ke              2025-11-11 @836  	return err;
39f4034693b7c7 Alexander Shishkin 2015-09-22  837  }
39f4034693b7c7 Alexander Shishkin 2015-09-22  838  

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