tree: https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git for-next/kspp head: 312cee4f1ab71ad56dde7c45fc3943341e712536 commit: 9bed5200e04d2a3dcd3a420d249e947eac7ec7c1 [4/6] Makefile: Enable -Wimplicit-fallthrough for Clang config: arm-randconfig-r023-20211013 (attached as .config) compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project 6c76d0101193aa4eb891a6954ff047eda2f9cf71) 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 # install arm cross compiling tool for clang build # apt-get install binutils-arm-linux-gnueabi # https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/comm... git remote add gustavoars https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git git fetch --no-tags gustavoars for-next/kspp git checkout 9bed5200e04d2a3dcd3a420d249e947eac7ec7c1 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 ARCH=arm 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 >>): case 0: ^ drivers/video/fbdev/omap/omapfb_main.c:1558:2: note: insert 'break;' to avoid fall-through case 0: ^ break; 1 warning generated. vim +1558 drivers/video/fbdev/omap/omapfb_main.c 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1521 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1522 /* 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1523 * Free driver resources. Can be called to rollback an aborted initialization 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1524 * sequence. 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1525 */ 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1526 static void omapfb_free_resources(struct omapfb_device *fbdev, int state) 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1527 { 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1528 int i; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1529 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1530 switch (state) { 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1531 case OMAPFB_ACTIVE: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1532 for (i = 0; i < fbdev->mem_desc.region_cnt; i++) 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1533 unregister_framebuffer(fbdev->fb_info[i]); df561f6688fef7 drivers/video/fbdev/omap/omapfb_main.c Gustavo A. R. Silva 2020-08-23 1534 fallthrough; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1535 case 7: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1536 omapfb_unregister_sysfs(fbdev); df561f6688fef7 drivers/video/fbdev/omap/omapfb_main.c Gustavo A. R. Silva 2020-08-23 1537 fallthrough; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1538 case 6: 561eb9d09a93d7 drivers/video/fbdev/omap/omapfb_main.c Lars-Peter Clausen 2017-01-30 1539 if (fbdev->panel->disable) 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1540 fbdev->panel->disable(fbdev->panel); df561f6688fef7 drivers/video/fbdev/omap/omapfb_main.c Gustavo A. R. Silva 2020-08-23 1541 fallthrough; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1542 case 5: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1543 omapfb_set_update_mode(fbdev, OMAPFB_UPDATE_DISABLED); df561f6688fef7 drivers/video/fbdev/omap/omapfb_main.c Gustavo A. R. Silva 2020-08-23 1544 fallthrough; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1545 case 4: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1546 planes_cleanup(fbdev); df561f6688fef7 drivers/video/fbdev/omap/omapfb_main.c Gustavo A. R. Silva 2020-08-23 1547 fallthrough; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1548 case 3: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1549 ctrl_cleanup(fbdev); df561f6688fef7 drivers/video/fbdev/omap/omapfb_main.c Gustavo A. R. Silva 2020-08-23 1550 fallthrough; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1551 case 2: 561eb9d09a93d7 drivers/video/fbdev/omap/omapfb_main.c Lars-Peter Clausen 2017-01-30 1552 if (fbdev->panel->cleanup) 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1553 fbdev->panel->cleanup(fbdev->panel); df561f6688fef7 drivers/video/fbdev/omap/omapfb_main.c Gustavo A. R. Silva 2020-08-23 1554 fallthrough; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1555 case 1: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1556 dev_set_drvdata(fbdev->dev, NULL); 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1557 kfree(fbdev); 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 @1558 case 0: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1559 /* nothing to free */ 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1560 break; 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1561 default: 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1562 BUG(); 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1563 } 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1564 } 8b08cf2b64f5a6 drivers/video/omap/omapfb_main.c Imre Deak 2007-07-17 1565 :::::: The code at line 1558 was first introduced by commit :::::: 8b08cf2b64f5a60594b07795b2ad518c6d044566 OMAP: add TI OMAP framebuffer driver :::::: TO: Imre Deak <imre.deak(a)solidboot.com&gt; :::::: CC: Linus Torvalds <torvalds(a)woody.linux-foundation.org&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org