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

[Mathieu Desnoyers <mathieu.desnoyers@efficios.com>]

On 2026-01-11 13:03, kernel test robot wrote:
> 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.

That's percpu_counter_tree_precise_sum which needs to return a "long".
Will fix.

> --
>>> 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;

I need to change this to "points_min = LONG_MAX". Will fix.

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com