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. 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
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