Hi Yu, Thank you for the patch! Yet something to improve: [auto build test ERROR on block/for-next] [also build test ERROR on v5.11-rc3 next-20210115] [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/Yu-Kuai/bfq-don-t-check-active-g... base: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git for-next config: arm-allyesconfig (attached as .config) compiler: arm-linux-gnueabi-gcc (GCC) 9.3.0 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 # https://github.com/0day-ci/linux/commit/2a2ab6f73f0608cec85e1f15254edc78a... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Yu-Kuai/bfq-don-t-check-active-group-if-bfq-weight-is-not-changed/20210115-112031 git checkout 2a2ab6f73f0608cec85e1f15254edc78a75d0366 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=arm 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 >>): arm-linux-gnueabi-ld: block/bfq-cgroup.o: in function `bfq_pd_init': arm-linux-gnueabi-ld: block/bfq-cgroup.o: in function `bfq_io_set_weight_legacy': bfq-cgroup.c:(.text+0x448): undefined reference to `__bad_cmpxchg' arm-linux-gnueabi-ld: block/bfq-cgroup.o: in function `bfq_io_set_weight': bfq-cgroup.c:(.text+0x1390): undefined reference to `__bad_cmpxchg' --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org