Hi Yonghong, I love your patch! Yet something to improve: [auto build test ERROR on next-20210318] [cannot apply to bpf-next/master bpf/master v5.12-rc3 v5.12-rc2 v5.12-rc1 v5.12-rc3] [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/Yonghong-Song/bpf-fix-NULL-point... base: ba5b053ab3ac674b91a6669086139819359a5e6e config: i386-randconfig-a005-20210318 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/38b56e03d083be940fe9dc231c5f6c8f4... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Yonghong-Song/bpf-fix-NULL-pointer-dereference-in/20210319-082140 git checkout 38b56e03d083be940fe9dc231c5f6c8f4f282f15 # save the attached .config to linux build tree make W=1 ARCH=i386 If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All errors (new ones prefixed by >>): In file included from include/asm-generic/percpu.h:7, from arch/x86/include/asm/percpu.h:390, from arch/x86/include/asm/current.h:6, from arch/x86/include/asm/processor.h:17, from arch/x86/include/asm/timex.h:5, from include/linux/timex.h:65, from include/linux/time32.h:13, from include/linux/time.h:60, from include/linux/ktime.h:24, from include/linux/timer.h:6, from include/linux/workqueue.h:9, from include/linux/bpf.h:9, from include/linux/bpf-cgroup.h:5, from kernel/bpf/local_storage.c:2: 13 | bpf_cgroup_storage_info[BPF_CGROUP_STORAGE_NEST_MAX]); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~ include/linux/percpu-defs.h:104:37: note: in definition of macro 'DEFINE_PER_CPU_SECTION' 104 | __PCPU_ATTRS(sec) __typeof__(type) name | ^~~~ kernel/bpf/local_storage.c:12:1: note: in expansion of macro 'DEFINE_PER_CPU' 12 | DEFINE_PER_CPU(struct bpf_cgroup_storage_info, | ^~~~~~~~~~~~~~ vim +13 kernel/bpf/local_storage.c 11 12 DEFINE_PER_CPU(struct bpf_cgroup_storage_info, 14 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org