Re: [PATCH v2] mm: page_alloc: dump migrate-failed pages

[Minchan Kim]

On Tue, Mar 09, 2021 at 05:29:30AM +0800, kernel test robot wrote:
> Hi Minchan,
> 
> I love your patch! Perhaps something to improve:
> 
> [auto build test WARNING on hnaz-linux-mm/master]
> 
> url:    https://github.com/0day-ci/linux/commits/Minchan-Kim/mm-page_alloc-dump-migrate-failed-pages/20210309-042205
> base:   https://github.com/hnaz/linux-mm master
> config: m68k-allmodconfig (attached as .config)
> compiler: m68k-linux-gcc (GCC) 9.3.0
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # https://github.com/0day-ci/linux/commit/3c635af37b862e9c601ee8d5818f7da9cd3e2e57
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Minchan-Kim/mm-page_alloc-dump-migrate-failed-pages/20210309-042205
>         git checkout 3c635af37b862e9c601ee8d5818f7da9cd3e2e57
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=m68k 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@xxxxxxxxx>
> 
> All warnings (new ones prefixed by >>):
> 
>    arch/m68k/include/asm/page_mm.h:169:49: warning: ordered comparison of pointer with null pointer [-Wextra]
>      169 | #define virt_addr_valid(kaddr) ((void *)(kaddr) >= (void *)PAGE_OFFSET && (void *)(kaddr) < high_memory)
>          |                                                 ^~
>    include/linux/compiler.h:78:42: note: in definition of macro 'unlikely'
>       78 | # define unlikely(x) __builtin_expect(!!(x), 0)
>          |                                          ^
>    include/linux/scatterlist.h:143:2: note: in expansion of macro 'BUG_ON'
>      143 |  BUG_ON(!virt_addr_valid(buf));
>          |  ^~~~~~
>    include/linux/scatterlist.h:143:10: note: in expansion of macro 'virt_addr_valid'
>      143 |  BUG_ON(!virt_addr_valid(buf));
>          |          ^~~~~~~~~~~~~~~
>    In file included from arch/m68k/include/asm/page.h:60,
>                     from arch/m68k/include/asm/thread_info.h:6,
>                     from include/linux/thread_info.h:38,
>                     from include/asm-generic/preempt.h:5,
>                     from ./arch/m68k/include/generated/asm/preempt.h:1,
>                     from include/linux/preempt.h:78,
>                     from include/linux/spinlock.h:51,
>                     from include/linux/mmzone.h:8,
>                     from include/linux/gfp.h:6,
>                     from include/linux/mm.h:10,
>                     from mm/page_alloc.c:19:

I am not sure this is triggered by the patch since I could see the
warn with reverting the patch.