Hi Dan, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable-rc.git linux-4.4.y head: 38c92ba3580f0d00e57a55caf8f880aa1a0f2a50 commit: ade5180681d778d36b569ad35cc175ab22196c5f [1449/1774] Input: joydev - prevent potential read overflow in ioctl config: mips-randconfig-r013-20210705 (attached as .config) compiler: mips64el-linux-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://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 ade5180681d778d36b569ad35cc175ab22196c5f # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=mips If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot <lkp(a)intel.com&gt; All warnings (new ones prefixed by >>): drivers/input/joydev.c: In function 'joydev_handle_JSIOCSAXMAP': 451 | for (i = 0; i < len && i < joydev->nabs; i++) { | ^ drivers/input/joydev.c: In function 'joydev_handle_JSIOCSBTNMAP': drivers/input/joydev.c:485:16: warning: comparison of integer expressions of different signedness: 'int' and 'size_t' {aka 'long unsigned int'} [-Wsign-compare] 485 | for (i = 0; i < (len / 2) && i < joydev->nkey; i++) { | ^ drivers/input/joydev.c: In function 'joydev_ioctl_common': drivers/input/joydev.c:566:52: warning: operand of ?: changes signedness from 'int' to 'size_t' {aka 'long unsigned int'} due to unsignedness of other operand [-Wsign-compare] 566 | return copy_to_user(argp, joydev->abspam, len) ? -EFAULT : len; drivers/input/joydev.c:573:52: warning: operand of ?: changes signedness from 'int' to 'size_t' {aka 'long unsigned int'} due to unsignedness of other operand [-Wsign-compare] 573 | return copy_to_user(argp, joydev->keypam, len) ? -EFAULT : len; drivers/input/joydev.c:581:42: warning: operand of ?: changes signedness from 'int' to 'size_t' {aka 'long unsigned int'} due to unsignedness of other operand [-Wsign-compare] 581 | return copy_to_user(argp, name, len) ? -EFAULT : len; vim +451 drivers/input/joydev.c 436 437 static int joydev_handle_JSIOCSAXMAP(struct joydev *joydev, 438 void __user *argp, size_t len) 439 { 440 __u8 *abspam; 441 int i; 442 int retval = 0; 443 444 len = min(len, sizeof(joydev->abspam)); 445 446 /* Validate the map. */ 447 abspam = memdup_user(argp, len); 448 if (IS_ERR(abspam)) 449 return PTR_ERR(abspam); 450 452 if (abspam[i] > ABS_MAX) { 453 retval = -EINVAL; 454 goto out; 455 } 456 } 457 458 memcpy(joydev->abspam, abspam, len); 459 460 for (i = 0; i < joydev->nabs; i++) 461 joydev->absmap[joydev->abspam[i]] = i; 462 463 out: 464 kfree(abspam); 465 return retval; 466 } 467 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org