tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.4.y head: 97fdbef74916fdbf7b965f6d0af619c09fc650bc commit: cbd4cbc1e68408305476174479579276accd3595 [9896/9999] powerpc/spufs: fix copy_to_user while atomic config: powerpc-cell_defconfig (attached as .config) compiler: powerpc64-linux-gcc (GCC) 7.5.0 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://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.gi... git remote add linux-stable-rc https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git git fetch --no-tags linux-stable-rc linux-4.4.y git checkout cbd4cbc1e68408305476174479579276accd3595 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-7.5.0 make.cross ARCH=powerpc 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 arch/powerpc/platforms/cell/spufs/file.c:28:0: include/linux/pagemap.h: In function 'fault_in_multipages_readable': include/linux/pagemap.h:632:16: error: variable 'c' set but not used [-Werror=unused-but-set-variable] volatile char c; ^ arch/powerpc/platforms/cell/spufs/file.c: In function 'spufs_regs_read': arch/powerpc/platforms/cell/spufs/file.c:492:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (*pos >= sizeof(ctx->csa.lscsa->gprs)) ^~ arch/powerpc/platforms/cell/spufs/file.c: In function 'spufs_regs_write': arch/powerpc/platforms/cell/spufs/file.c:511:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (*pos >= sizeof(lscsa->gprs)) ^~ arch/powerpc/platforms/cell/spufs/file.c: In function 'spufs_fpcr_write': arch/powerpc/platforms/cell/spufs/file.c:564:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (*pos >= sizeof(lscsa->fpcr)) ^~ arch/powerpc/platforms/cell/spufs/file.c: In function 'spufs_mbox_read': arch/powerpc/platforms/cell/spufs/file.c:621:30: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] for (count = 0; (count + 4) <= len; count += 4, udata++) { ^~ arch/powerpc/platforms/cell/spufs/file.c: In function 'spufs_ibox_read': arch/powerpc/platforms/cell/spufs/file.c:757:39: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) { ^~ arch/powerpc/platforms/cell/spufs/file.c: In function 'spufs_wbox_write': arch/powerpc/platforms/cell/spufs/file.c:911:39: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) { ^~ arch/powerpc/platforms/cell/spufs/file.c: In function '__spufs_wbox_info_read': u32 wbox_stat; ^~~~~~~~~ arch/powerpc/platforms/cell/spufs/file.c: In function '__spufs_proxydma_info_read': arch/powerpc/platforms/cell/spufs/file.c:2259:10: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (len < ret) ^ arch/powerpc/platforms/cell/spufs/file.c: In function 'spufs_switch_log_read': arch/powerpc/platforms/cell/spufs/file.c:2494:13: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] while (cnt < len) { ^ arch/powerpc/platforms/cell/spufs/file.c:2531:13: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (width < len) ^ cc1: all warnings being treated as errors vim +/wbox_stat +2132 arch/powerpc/platforms/cell/spufs/file.c cbd4cbc1e684083 Jeremy Kerr 2020-05-05 2126 bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2127 static ssize_t __spufs_wbox_info_read(struct spu_context *ctx, bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2128 char __user *buf, size_t len, loff_t *pos) 69a2f00ce5d3a19 Dwayne Grant McConnell 2006-11-20 2129 { 69a2f00ce5d3a19 Dwayne Grant McConnell 2006-11-20 2130 int i, cnt; 69a2f00ce5d3a19 Dwayne Grant McConnell 2006-11-20 2131 u32 data[4]; 69a2f00ce5d3a19 Dwayne Grant McConnell 2006-11-20 @2132 u32 wbox_stat; 69a2f00ce5d3a19 Dwayne Grant McConnell 2006-11-20 2133 bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2134 wbox_stat = ctx->csa.prob.mb_stat_R; cbd4cbc1e684083 Jeremy Kerr 2020-05-05 2135 cnt = spufs_wbox_info_cnt(ctx); bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2136 for (i = 0; i < cnt; i++) { bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2137 data[i] = ctx->csa.spu_mailbox_data[i]; bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2138 } bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2139 bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2140 return simple_read_from_buffer(buf, len, pos, &data, bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2141 cnt * sizeof(u32)); bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2142 } bf1ab978be2318c Dwayne Grant McConnell 2006-11-23 2143 :::::: The code at line 2132 was first introduced by commit :::::: 69a2f00ce5d3a19a70b36f08eaf9049677277710 [POWERPC] spufs: Implement /mbox_info, /ibox_info, and /wbox_info. :::::: TO: Dwayne Grant McConnell <decimal(a)us.ibm.com&gt; :::::: CC: Paul Mackerras <paulus(a)samba.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org