Re: [PATCH v3 4/6] mm: shmem: add mTHP support for anonymous shmem

[Baolin Wang]

On 2024/5/30 14:36, kernel test robot wrote:
> Hi Baolin,
>
> kernel test robot noticed the following build warnings:
>
> [auto build test WARNING on akpm-mm/mm-everything]
> [also build test WARNING on next-20240529]
> [cannot apply to linus/master v6.10-rc1]
> [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/Baolin-Wang/mm-memory-extend-finish_fault-to-support-large-folio/20240530-100805
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-everything
> patch link:    https://lore.kernel.org/r/ec35a23026dd016705d211e85163cabe07681516.1717033868.git.baolin.wang%40linux.alibaba.com
> patch subject: [PATCH v3 4/6] mm: shmem: add mTHP support for anonymous shmem
> config: riscv-defconfig (https://download.01.org/0day-ci/archive/20240530/202405301430.0NRLTOWU-lkp@xxxxxxxxx/config)
> compiler: clang version 19.0.0git (https://github.com/llvm/llvm-project bafda89a0944d947fc4b3b5663185e07a397ac30)
> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240530/202405301430.0NRLTOWU-lkp@xxxxxxxxx/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@xxxxxxxxx>
> | Closes: https://lore.kernel.org/oe-kbuild-all/202405301430.0NRLTOWU-lkp@xxxxxxxxx/
>
> All warnings (new ones prefixed by >>):
>
>     In file included from mm/shmem.c:28:
>     In file included from include/linux/ramfs.h:5:
>     In file included from include/linux/fs_parser.h:11:
>     In file included from include/linux/fs_context.h:14:
>     In file included from include/linux/security.h:33:
>     In file included from include/linux/mm.h:2245:
>     include/linux/vmstat.h:514:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
>       514 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
>           |                               ~~~~~~~~~~~ ^ ~~~
> > > mm/shmem.c:1748:14: warning: variable 'suitable_orders' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
>      1748 |                 } else if (orders & BIT(HPAGE_PMD_ORDER)) {
>           |                            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>     mm/shmem.c:1766:25: note: uninitialized use occurs here
>      1766 |                 order = highest_order(suitable_orders);
>           |                                       ^~~~~~~~~~~~~~~
>     mm/shmem.c:1748:10: note: remove the 'if' if its condition is always true
>      1748 |                 } else if (orders & BIT(HPAGE_PMD_ORDER)) {
>           |                        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>     mm/shmem.c:1736:31: note: initialize the variable 'suitable_orders' to silence this warning
>      1736 |         unsigned long suitable_orders;
>           |                                      ^
>           |                                       = 0
>     2 warnings generated.

Thanks for reporting. Will fix the warning in next version.