Re: [PATCH 1/8] powerpc/mm: Make slice specific to book3s/64

[Christophe Leroy <christophe.leroy@csgroup.eu>]

Le 24/11/2021 à 13:10, Christophe Leroy a écrit :
> 
> 
> Le 22/11/2021 à 15:48, kernel test robot a écrit :
>> Hi Christophe,
>>
>> I love your patch! Perhaps something to improve:
>>
>> [auto build test WARNING on powerpc/next]
>> [also build test WARNING on hnaz-mm/master linus/master v5.16-rc2 
>> next-20211118]
>> [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]
>>
>> url:    
>> https://github.com/0day-ci/linux/commits/Christophe-Leroy/Convert-powerpc-to-default-topdown-mmap-layout/20211122-165115 
>>
>> base:   
>> https://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux.git next
>> config: powerpc64-randconfig-s031-20211122 (attached as .config)
>> compiler: powerpc64-linux-gcc (GCC) 11.2.0
>> reproduce:
>>          wget 
>> https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross 
>> -O ~/bin/make.cross
>>          chmod +x ~/bin/make.cross
>>          # apt-get install sparse
>>          # sparse version: v0.6.4-dirty
>>          # 
>> https://github.com/0day-ci/linux/commit/1d0b7cc86d08f25f595b52d8c39ba9ca1d29a30a 
>>
>>          git remote add linux-review https://github.com/0day-ci/linux
>>          git fetch --no-tags linux-review 
>> Christophe-Leroy/Convert-powerpc-to-default-topdown-mmap-layout/20211122-165115 
>>
>>          git checkout 1d0b7cc86d08f25f595b52d8c39ba9ca1d29a30a
>>          # save the attached .config to linux build tree
>>          COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 
>> make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=powerpc64
>>
>> If you fix the issue, kindly add following tag as appropriate
>> Reported-by: kernel test robot <lkp@intel.com>
>>
>> All warnings (new ones prefixed by >>):
>>
>>     arch/powerpc/mm/book3s64/slice.c: In function 
>> 'slice_get_unmapped_area':
>>>> arch/powerpc/mm/book3s64/slice.c:639:1: warning: the frame size of 
>>>> 1040 bytes is larger than 1024 bytes [-Wframe-larger-than=]
>>       639 | }
>>           | ^
> 
> 
> The problem was already existing when slice.c was in arch/powerpc/mm/
> 
> This patch doesn't introduce the problem.
> 

In fact the problem is really added by yourself mister 'kernel test robot'.

CONFIG_FRAME_WARN is supposed to be 2048 on 64 bit architectures.

It the robot starts to reduce that value, it is on its own ....


config FRAME_WARN
	int "Warn for stack frames larger than"
	range 0 8192
	default 2048 if GCC_PLUGIN_LATENT_ENTROPY
	default 1536 if (!64BIT && (PARISC || XTENSA))
	default 1024 if (!64BIT && !PARISC)
	default 2048 if 64BIT
	help
	  Tell gcc to warn at build time for stack frames larger than this.
	  Setting this too low will cause a lot of warnings.
	  Setting it to 0 disables the warning.