Re: [PATCH v12 3/3] mm: Implement precise OOM killer task selection

[kernel test robot <lkp@intel.com>]

Hi Mathieu,

kernel test robot noticed the following build warnings:

[auto build test WARNING on next-20260109]
[cannot apply to akpm-mm/mm-everything kees/for-next/execve tip/sched/core linus/master v6.19-rc4 v6.19-rc3 v6.19-rc2 v6.19-rc4]
[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/Mathieu-Desnoyers/lib-Introduce-hierarchical-per-cpu-counters/20260111-231206
base:   next-20260109
patch link:    https://lore.kernel.org/r/20260111150249.1222944-4-mathieu.desnoyers%40efficios.com
patch subject: [PATCH v12 3/3] mm: Implement precise OOM killer task selection
config: arm-randconfig-001-20260112 (https://download.01.org/0day-ci/archive/20260112/202601120124.RK3AWOwu-lkp@intel.com/config)
compiler: clang version 22.0.0git (https://github.com/llvm/llvm-project 9b8addffa70cee5b2acc5454712d9cf78ce45710)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20260112/202601120124.RK3AWOwu-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/202601120124.RK3AWOwu-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> kernel/fork.c:637:6: warning: format specifies type 'long' but the argument has type 'int' [-Wformat]
     635 |                         pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld Comm:%s Pid:%d\n",
         |                                                                                ~~~
         |                                                                                %d
     636 |                                  mm, resident_page_types[i],
     637 |                                  percpu_counter_tree_precise_sum(&mm->rss_stat[i]),
         |                                  ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   include/linux/printk.h:534:35: note: expanded from macro 'pr_alert'
     534 |         printk(KERN_ALERT pr_fmt(fmt), ##__VA_ARGS__)
         |                                  ~~~     ^~~~~~~~~~~
   include/linux/printk.h:511:60: note: expanded from macro 'printk'
     511 | #define printk(fmt, ...) printk_index_wrap(_printk, fmt, ##__VA_ARGS__)
         |                                                     ~~~    ^~~~~~~~~~~
   include/linux/printk.h:483:19: note: expanded from macro 'printk_index_wrap'
     483 |                 _p_func(_fmt, ##__VA_ARGS__);                           \
         |                         ~~~~    ^~~~~~~~~~~
   1 warning generated.
--
>> mm/oom_kill.c:351:6: warning: variable 'points_min' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]
     351 |         if (oom_task_origin(task)) {
         |             ^~~~~~~~~~~~~~~~~~~~~
   mm/oom_kill.c:392:22: note: uninitialized use occurs here
     392 |         oc->chosen_points = points_min;
         |                             ^~~~~~~~~~
   mm/oom_kill.c:351:2: note: remove the 'if' if its condition is always false
     351 |         if (oom_task_origin(task)) {
         |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~
     352 |                 points = LONG_MAX;
         |                 ~~~~~~~~~~~~~~~~~~
     353 |                 goto select;
         |                 ~~~~~~~~~~~~
     354 |         }
         |         ~
   mm/oom_kill.c:326:25: note: initialize the variable 'points_min' to silence this warning
     326 |         long points, points_min, points_max;
         |                                ^
         |                                 = 0
   1 warning generated.


vim +637 kernel/fork.c

6af8cb80d3a9a6 David Hildenbrand    2025-03-03  625  
d70f2a14b72a4b Andrew Morton        2018-01-31  626  static void check_mm(struct mm_struct *mm)
d70f2a14b72a4b Andrew Morton        2018-01-31  627  {
d70f2a14b72a4b Andrew Morton        2018-01-31  628  	int i;
d70f2a14b72a4b Andrew Morton        2018-01-31  629  
8495f7e6732ed2 Sai Praneeth Prakhya 2019-09-25  630  	BUILD_BUG_ON_MSG(ARRAY_SIZE(resident_page_types) != NR_MM_COUNTERS,
8495f7e6732ed2 Sai Praneeth Prakhya 2019-09-25  631  			 "Please make sure 'struct resident_page_types[]' is updated as well");
8495f7e6732ed2 Sai Praneeth Prakhya 2019-09-25  632  
d70f2a14b72a4b Andrew Morton        2018-01-31  633  	for (i = 0; i < NR_MM_COUNTERS; i++) {
25d942f31cc499 Mathieu Desnoyers    2026-01-11  634  		if (unlikely(percpu_counter_tree_precise_compare_value(&mm->rss_stat[i], 0) != 0))
72456781289a6e Mathieu Desnoyers    2026-01-11  635  			pr_alert("BUG: Bad rss-counter state mm:%p type:%s val:%ld Comm:%s Pid:%d\n",
25d942f31cc499 Mathieu Desnoyers    2026-01-11  636  				 mm, resident_page_types[i],
25d942f31cc499 Mathieu Desnoyers    2026-01-11 @637  				 percpu_counter_tree_precise_sum(&mm->rss_stat[i]),
881388f3433819 Xuanye Liu           2025-07-23  638  				 current->comm,
881388f3433819 Xuanye Liu           2025-07-23  639  				 task_pid_nr(current));
881388f3433819 Xuanye Liu           2025-07-23  640  	}
d70f2a14b72a4b Andrew Morton        2018-01-31  641  
d70f2a14b72a4b Andrew Morton        2018-01-31  642  	if (mm_pgtables_bytes(mm))
d70f2a14b72a4b Andrew Morton        2018-01-31  643  		pr_alert("BUG: non-zero pgtables_bytes on freeing mm: %ld\n",
d70f2a14b72a4b Andrew Morton        2018-01-31  644  				mm_pgtables_bytes(mm));
d70f2a14b72a4b Andrew Morton        2018-01-31  645  

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