tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: da2968ff879b9e74688cdc658f646971991d2c56 commit: df8df5e4bc37e39010cfdf5d50cf726fe08aae5b usb: get rid of 'choice' for legacy gadget drivers date: 5 months ago config: powerpc-randconfig-s032-20200821 (attached as .config) compiler: powerpc64-linux-gcc (GCC) 9.3.0 reproduce: wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross chmod +x ~/bin/make.cross # apt-get install sparse # sparse version: v0.6.2-191-g10164920-dirty git checkout df8df5e4bc37e39010cfdf5d50cf726fe08aae5b # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=powerpc If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; sparse warnings: (new ones prefixed by >>) drivers/usb/gadget/legacy/inode.c: note: in included file (through arch/powerpc/include/asm/mmiowb.h, include/linux/spinlock.h, include/linux/seqlock.h, ...): # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout df8df5e4bc37e39010cfdf5d50cf726fe08aae5b vim +/ep0_write +56 include/asm-generic/mmiowb.h d1be6a28b13ce6 Will Deacon 2019-02-22 46 d1be6a28b13ce6 Will Deacon 2019-02-22 47 static inline void mmiowb_spin_unlock(void) d1be6a28b13ce6 Will Deacon 2019-02-22 48 { d1be6a28b13ce6 Will Deacon 2019-02-22 49 struct mmiowb_state *ms = __mmiowb_state(); d1be6a28b13ce6 Will Deacon 2019-02-22 50 d1be6a28b13ce6 Will Deacon 2019-02-22 51 if (unlikely(ms->mmiowb_pending)) { d1be6a28b13ce6 Will Deacon 2019-02-22 52 ms->mmiowb_pending = 0; d1be6a28b13ce6 Will Deacon 2019-02-22 53 mmiowb(); d1be6a28b13ce6 Will Deacon 2019-02-22 54 } d1be6a28b13ce6 Will Deacon 2019-02-22 55 d1be6a28b13ce6 Will Deacon 2019-02-22 @56 ms->nesting_count--; :::::: The code at line 56 was first introduced by commit :::::: d1be6a28b13ce6d1bc42bf9b6a9454c65839225b asm-generic/mmiowb: Add generic implementation of mmiowb() tracking :::::: TO: Will Deacon <will.deacon(a)arm.com&gt; :::::: CC: Will Deacon <will.deacon(a)arm.com&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org