Re: [PATCH] kernel/workqueue: Remove unnecessary ‘0’ values from hash

From: kernel test robot <lkp@intel.com>
To: Li zeming <zeming@nfschina.com>, tj@kernel.org, jiangshanlai@gmail.com
Cc: oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org,
	Li zeming <zeming@nfschina.com>
Subject: Re: [PATCH] kernel/workqueue: Remove unnecessary ‘0’ values from hash
Date: Thu, 12 Oct 2023 23:06:12 +0800	[thread overview]
Message-ID: <202310122246.FzszMZbr-lkp@intel.com> (raw)
In-Reply-To: <20230829181755.3204-1-zeming@nfschina.com>

Hi Li,

kernel test robot noticed the following build warnings:

[auto build test WARNING on tj-wq/for-next]
[also build test WARNING on linus/master v6.6-rc5 next-20231012]
[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/Li-zeming/kernel-workqueue-Remove-unnecessary-0-values-from-hash/20230828-095048
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tj/wq.git for-next
patch link:    https://lore.kernel.org/r/20230829181755.3204-1-zeming%40nfschina.com
patch subject: [PATCH] kernel/workqueue: Remove unnecessary ‘0’ values from hash
config: powerpc-allnoconfig (https://download.01.org/0day-ci/archive/20231012/202310122246.FzszMZbr-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231012/202310122246.FzszMZbr-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/202310122246.FzszMZbr-lkp@intel.com/

All warnings (new ones prefixed by >>):

   kernel/workqueue.c: In function 'wqattrs_hash':
>> kernel/workqueue.c:3777:16: warning: 'hash' is used uninitialized [-Wuninitialized]
    3777 |         hash = jhash_1word(attrs->nice, hash);
         |                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   kernel/workqueue.c:3775:13: note: 'hash' was declared here
    3775 |         u32 hash;
         |             ^~~~

vim +/hash +3777 kernel/workqueue.c

5de7a03cac1476 Tejun Heo           2023-08-07  3771  
6ba94429c8e7b8 Frederic Weisbecker 2015-04-02  3772  /* hash value of the content of @attr */
6ba94429c8e7b8 Frederic Weisbecker 2015-04-02  3773  static u32 wqattrs_hash(const struct workqueue_attrs *attrs)
226223ab3c4118 Tejun Heo           2013-03-12  3774  {
dd46423224bbdf Li zeming           2023-08-30  3775  	u32 hash;
226223ab3c4118 Tejun Heo           2013-03-12  3776  
6ba94429c8e7b8 Frederic Weisbecker 2015-04-02 @3777  	hash = jhash_1word(attrs->nice, hash);
6ba94429c8e7b8 Frederic Weisbecker 2015-04-02  3778  	hash = jhash(cpumask_bits(attrs->cpumask),
6ba94429c8e7b8 Frederic Weisbecker 2015-04-02  3779  		     BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
9546b29e4a6ad6 Tejun Heo           2023-08-07  3780  	hash = jhash(cpumask_bits(attrs->__pod_cpumask),
9546b29e4a6ad6 Tejun Heo           2023-08-07  3781  		     BITS_TO_LONGS(nr_cpumask_bits) * sizeof(long), hash);
8639ecebc9b179 Tejun Heo           2023-08-07  3782  	hash = jhash_1word(attrs->affn_strict, hash);
6ba94429c8e7b8 Frederic Weisbecker 2015-04-02  3783  	return hash;
d55262c4d16475 Tejun Heo           2013-04-01  3784  }
226223ab3c4118 Tejun Heo           2013-03-12  3785  

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