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Date:   Thu, 2 Nov 2023 16:42:42 +0800
From:   kernel test robot <lkp@intel.com>
To:     "Liam R. Howlett" <Liam.Howlett@oracle.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     oe-kbuild-all@lists.linux.dev,
        Linux Memory Management List <linux-mm@kvack.org>,
        maple-tree@lists.infradead.org, linux-kernel@vger.kernel.org,
        "Liam R. Howlett" <Liam.Howlett@oracle.com>
Subject: Re: [PATCH 08/12] maple_tree: Separate ma_state node from status.
Message-ID: <202311021622.6KoUHJP7-lkp@intel.com>
References: <20231101171629.3612299-9-Liam.Howlett@oracle.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
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In-Reply-To: <20231101171629.3612299-9-Liam.Howlett@oracle.com>
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Hi Liam,

kernel test robot noticed the following build warnings:

[auto build test WARNING on akpm-mm/mm-everything]
[also build test WARNING on linus/master v6.6 next-20231102]
[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/Liam-R-Howlett/maple_tree-Remove-unnecessary-default-labels-from-switch-statements/20231102-033618
base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
patch link:    https://lore.kernel.org/r/20231101171629.3612299-9-Liam.Howlett%40oracle.com
patch subject: [PATCH 08/12] maple_tree: Separate ma_state node from status.
config: arc-randconfig-001-20231102 (https://download.01.org/0day-ci/archive/20231102/202311021622.6KoUHJP7-lkp@intel.com/config)
compiler: arceb-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231102/202311021622.6KoUHJP7-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/202311021622.6KoUHJP7-lkp@intel.com/

All warnings (new ones prefixed by >>):

   drivers/base/regmap/regcache-maple.c: In function 'regcache_maple_drop':
   drivers/base/regmap/regcache-maple.c:113:23: warning: 'lower_index' is used uninitialized [-Wuninitialized]
     113 |         unsigned long lower_index, lower_last;
         |                       ^~~~~~~~~~~
   drivers/base/regmap/regcache-maple.c:113:36: warning: 'lower_last' is used uninitialized [-Wuninitialized]
     113 |         unsigned long lower_index, lower_last;
         |                                    ^~~~~~~~~~
>> drivers/base/regmap/regcache-maple.c:114:23: warning: 'upper_index' is used uninitialized [-Wuninitialized]
     114 |         unsigned long upper_index, upper_last;
         |                       ^~~~~~~~~~~
>> drivers/base/regmap/regcache-maple.c:114:36: warning: 'upper_last' is used uninitialized [-Wuninitialized]
     114 |         unsigned long upper_index, upper_last;
         |                                    ^~~~~~~~~~


vim +/upper_index +114 drivers/base/regmap/regcache-maple.c

f033c26de5a5734 Mark Brown    2023-03-30  106  
f033c26de5a5734 Mark Brown    2023-03-30  107  static int regcache_maple_drop(struct regmap *map, unsigned int min,
f033c26de5a5734 Mark Brown    2023-03-30  108  			       unsigned int max)
f033c26de5a5734 Mark Brown    2023-03-30  109  {
f033c26de5a5734 Mark Brown    2023-03-30  110  	struct maple_tree *mt = map->cache;
f033c26de5a5734 Mark Brown    2023-03-30  111  	MA_STATE(mas, mt, min, max);
f033c26de5a5734 Mark Brown    2023-03-30  112  	unsigned long *entry, *lower, *upper;
f033c26de5a5734 Mark Brown    2023-03-30  113  	unsigned long lower_index, lower_last;
f033c26de5a5734 Mark Brown    2023-03-30 @114  	unsigned long upper_index, upper_last;
f033c26de5a5734 Mark Brown    2023-03-30  115  	int ret;
f033c26de5a5734 Mark Brown    2023-03-30  116  
f033c26de5a5734 Mark Brown    2023-03-30  117  	lower = NULL;
f033c26de5a5734 Mark Brown    2023-03-30  118  	upper = NULL;
f033c26de5a5734 Mark Brown    2023-03-30  119  
f033c26de5a5734 Mark Brown    2023-03-30  120  	mas_lock(&mas);
f033c26de5a5734 Mark Brown    2023-03-30  121  
f033c26de5a5734 Mark Brown    2023-03-30  122  	mas_for_each(&mas, entry, max) {
f033c26de5a5734 Mark Brown    2023-03-30  123  		/*
f033c26de5a5734 Mark Brown    2023-03-30  124  		 * This is safe because the regmap lock means the
f033c26de5a5734 Mark Brown    2023-03-30  125  		 * Maple lock is redundant, but we need to take it due
f033c26de5a5734 Mark Brown    2023-03-30  126  		 * to lockdep asserts in the maple tree code.
f033c26de5a5734 Mark Brown    2023-03-30  127  		 */
f033c26de5a5734 Mark Brown    2023-03-30  128  		mas_unlock(&mas);
f033c26de5a5734 Mark Brown    2023-03-30  129  
f033c26de5a5734 Mark Brown    2023-03-30  130  		/* Do we need to save any of this entry? */
f033c26de5a5734 Mark Brown    2023-03-30  131  		if (mas.index < min) {
f033c26de5a5734 Mark Brown    2023-03-30  132  			lower_index = mas.index;
f033c26de5a5734 Mark Brown    2023-03-30  133  			lower_last = min -1;
f033c26de5a5734 Mark Brown    2023-03-30  134  
f033c26de5a5734 Mark Brown    2023-03-30  135  			lower = kmemdup(entry, ((min - mas.index) *
f033c26de5a5734 Mark Brown    2023-03-30  136  						sizeof(unsigned long)),
b0393e1fe40e962 Guenter Roeck 2023-07-20  137  					map->alloc_flags);
f033c26de5a5734 Mark Brown    2023-03-30  138  			if (!lower) {
f033c26de5a5734 Mark Brown    2023-03-30  139  				ret = -ENOMEM;
451941ac1ee2be1 Mark Brown    2023-04-03  140  				goto out_unlocked;
f033c26de5a5734 Mark Brown    2023-03-30  141  			}
f033c26de5a5734 Mark Brown    2023-03-30  142  		}
f033c26de5a5734 Mark Brown    2023-03-30  143  
f033c26de5a5734 Mark Brown    2023-03-30  144  		if (mas.last > max) {
f033c26de5a5734 Mark Brown    2023-03-30  145  			upper_index = max + 1;
f033c26de5a5734 Mark Brown    2023-03-30  146  			upper_last = mas.last;
f033c26de5a5734 Mark Brown    2023-03-30  147  
f033c26de5a5734 Mark Brown    2023-03-30  148  			upper = kmemdup(&entry[max + 1],
f033c26de5a5734 Mark Brown    2023-03-30  149  					((mas.last - max) *
f033c26de5a5734 Mark Brown    2023-03-30  150  					 sizeof(unsigned long)),
b0393e1fe40e962 Guenter Roeck 2023-07-20  151  					map->alloc_flags);
f033c26de5a5734 Mark Brown    2023-03-30  152  			if (!upper) {
f033c26de5a5734 Mark Brown    2023-03-30  153  				ret = -ENOMEM;
451941ac1ee2be1 Mark Brown    2023-04-03  154  				goto out_unlocked;
f033c26de5a5734 Mark Brown    2023-03-30  155  			}
f033c26de5a5734 Mark Brown    2023-03-30  156  		}
f033c26de5a5734 Mark Brown    2023-03-30  157  
f033c26de5a5734 Mark Brown    2023-03-30  158  		kfree(entry);
f033c26de5a5734 Mark Brown    2023-03-30  159  		mas_lock(&mas);
f033c26de5a5734 Mark Brown    2023-03-30  160  		mas_erase(&mas);
f033c26de5a5734 Mark Brown    2023-03-30  161  
f033c26de5a5734 Mark Brown    2023-03-30  162  		/* Insert new nodes with the saved data */
f033c26de5a5734 Mark Brown    2023-03-30  163  		if (lower) {
f033c26de5a5734 Mark Brown    2023-03-30  164  			mas_set_range(&mas, lower_index, lower_last);
b0393e1fe40e962 Guenter Roeck 2023-07-20  165  			ret = mas_store_gfp(&mas, lower, map->alloc_flags);
f033c26de5a5734 Mark Brown    2023-03-30  166  			if (ret != 0)
f033c26de5a5734 Mark Brown    2023-03-30  167  				goto out;
f033c26de5a5734 Mark Brown    2023-03-30  168  			lower = NULL;
f033c26de5a5734 Mark Brown    2023-03-30  169  		}
f033c26de5a5734 Mark Brown    2023-03-30  170  
f033c26de5a5734 Mark Brown    2023-03-30  171  		if (upper) {
f033c26de5a5734 Mark Brown    2023-03-30  172  			mas_set_range(&mas, upper_index, upper_last);
b0393e1fe40e962 Guenter Roeck 2023-07-20  173  			ret = mas_store_gfp(&mas, upper, map->alloc_flags);
f033c26de5a5734 Mark Brown    2023-03-30  174  			if (ret != 0)
f033c26de5a5734 Mark Brown    2023-03-30  175  				goto out;
f033c26de5a5734 Mark Brown    2023-03-30  176  			upper = NULL;
f033c26de5a5734 Mark Brown    2023-03-30  177  		}
f033c26de5a5734 Mark Brown    2023-03-30  178  	}
f033c26de5a5734 Mark Brown    2023-03-30  179  
f033c26de5a5734 Mark Brown    2023-03-30  180  out:
f033c26de5a5734 Mark Brown    2023-03-30  181  	mas_unlock(&mas);
451941ac1ee2be1 Mark Brown    2023-04-03  182  out_unlocked:
f033c26de5a5734 Mark Brown    2023-03-30  183  	kfree(lower);
f033c26de5a5734 Mark Brown    2023-03-30  184  	kfree(upper);
f033c26de5a5734 Mark Brown    2023-03-30  185  
f033c26de5a5734 Mark Brown    2023-03-30  186  	return ret;
f033c26de5a5734 Mark Brown    2023-03-30  187  }
f033c26de5a5734 Mark Brown    2023-03-30  188  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki