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@xxxxxxxxx> > > 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@xxxxxxxxxx/ which it seems never got picked up :( Cheers, Nathan > vim +52 fs/sysfs/file.c > > 35 > 36 /* > 37 * To be proactively defensive against sysfs show() handlers that do not > 38 * correctly stay within their PAGE_SIZE buffer, use the vmap area to gain > 39 * the trailing guard page which will stop linear buffer overflows. > 40 */ > 41 static void *sysfs_kf_seq_start(struct seq_file *sf, loff_t *ppos) > 42 { > 43 struct kernfs_open_file *of = sf->private; > 44 struct kernfs_node *kn = of->kn; > 45 > 46 WARN_ON_ONCE(sf->buf); > 47 sf->buf = __vmalloc(kn->attr.size, GFP_KERNEL_ACCOUNT); > 48 if (!sf->buf) > 49 return ERR_PTR(-ENOMEM); > 50 sf->size = kn->attr.size; > 51 > > 52 return NULL + !*ppos; > 53 } > 54 > > --- > 0-DAY CI Kernel Test Service, Intel Corporation > https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx
