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

[Christophe Leroy]

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@xxxxxxxxx>
> >
> > 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.