Re: [PATCH v3] sysfs: Unconditionally use vmalloc for buffer

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

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On Wed, Mar 31, 2021 at 11:59:03PM -0700, Kees Cook wrote:
> On Wed, Mar 31, 2021 at 11:47:53PM -0700, Nathan Chancellor wrote:
> > On Thu, Apr 01, 2021 at 02:41:37PM +0800, kernel test robot wrote:
> > > Hi Kees,
> > > 
> > > I love your patch! Perhaps something to improve:
> > > 
> > > [auto build test WARNING on driver-core/driver-core-testing]
> > > [also build test WARNING on kees/for-next/pstore v5.12-rc5 next-20210331]
> > > [cannot apply to hnaz-linux-mm/master]
> > > [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/Kees-Cook/sysfs-Unconditionally-use-vmalloc-for-buffer/20210401-102455
> > > base:   https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core.git d225ef6fda7ce9ff7d28764bd1cceea2d0215e8b
> > > config: powerpc-randconfig-r001-20210401 (attached as .config)
> > > compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 1c268a8ff4e90a85d0e634350b1104080614cf2b)
> > > 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
> > >         # install powerpc cross compiling tool for clang build
> > >         # apt-get install binutils-powerpc-linux-gnu
> > >         # https://github.com/0day-ci/linux/commit/c80ca56c15314908ebc1881678da3b36e007a2f4
> > >         git remote add linux-review https://github.com/0day-ci/linux
> > >         git fetch --no-tags linux-review Kees-Cook/sysfs-Unconditionally-use-vmalloc-for-buffer/20210401-102455
> > >         git checkout c80ca56c15314908ebc1881678da3b36e007a2f4
> > >         # save the attached .config to linux build tree
> > >         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=powerpc 
> > > 
> > > 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 >>):
> > > 
> > > >> fs/sysfs/file.c:52:14: warning: performing pointer arithmetic on a null pointer has undefined behavior [-Wnull-pointer-arithmetic]
> > >            return NULL + !*ppos;
> > >                   ~~~~ ^
> > >    1 warning generated.
> > > 
> > 
> > Arnd addressed other warnings of this nature in this patch:
> > 
> > https://lore.kernel.org/r/20201028151202.3074398-1-arnd(a)kernel.org/
> 
> Ah! Yeah, I copied exactly that clever idiom that Arnd fixed. :)
> 
> > which it seems never got picked up :(
> 
> Greg, are you able to pick this up too? (Yeow, sent in October!)
> (Or I could respin and send them as a series?)

As a series would be great, thanks.

greg k-h