tree: https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git 20210708-block-fixes-v2 head: db0174e39de7dc941f158ce53ee3af95b1635b62 commit: b253de076cda99b4968dd20b1a9702de24376152 [61/89] block: make __register_blkdev() return an error config: powerpc-randconfig-r005-20210715 (attached as .config) compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project 0e49c54a8cbd3e779e5526a5888c683c01cc3c50) 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 powerpc cross compiling tool for clang build # apt-get install binutils-powerpc-linux-gnu # https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git/com... git remote add mcgrof-next https://git.kernel.org/pub/scm/linux/kernel/git/mcgrof/linux-next.git git fetch --no-tags mcgrof-next 20210708-block-fixes-v2 git checkout b253de076cda99b4968dd20b1a9702de24376152 # save the attached .config to linux build tree COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang 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 error/warnings (new ones prefixed by >>): if (floppy_alloc_disk(drive, type) == 0) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/block/floppy.c:4540:9: note: uninitialized use occurs here return err; ^~~ drivers/block/floppy.c:4532:3: note: remove the 'if' if its condition is always true if (floppy_alloc_disk(drive, type) == 0) { ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ drivers/block/floppy.c:4531:6: warning: variable 'err' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] if (!disks[drive][type]) { ^~~~~~~~~~~~~~~~~~~ drivers/block/floppy.c:4540:9: note: uninitialized use occurs here return err; ^~~ drivers/block/floppy.c:4531:2: note: remove the 'if' if its condition is always true if (!disks[drive][type]) { ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/block/floppy.c:4524:9: note: initialize the variable 'err' to silence this warning int err; ^ = 0 2 warnings generated. -- ret = __register_blkdev(MD_MAJOR, "md", md_probe); ^~~~~~~~ include/linux/genhd.h:315:9: note: passing argument to parameter 'probe' here int (*probe)(dev_t devt)); ^ drivers/md/md.c:9596:36: error: incompatible function pointer types passing 'void (dev_t)' (aka 'void (unsigned int)') to parameter of type 'int (*)(dev_t)' (aka 'int (*)(unsigned int)') [-Werror,-Wincompatible-function-pointer-types] ret = __register_blkdev(0, "mdp", md_probe); ^~~~~~~~ include/linux/genhd.h:315:9: note: passing argument to parameter 'probe' here int (*probe)(dev_t devt)); ^ 2 errors generated. vim +9592 drivers/md/md.c ^1da177e4c3f41 Linus Torvalds 2005-04-16 9575 75c96f85845a67 Adrian Bunk 2005-05-05 9576 static int __init md_init(void) ^1da177e4c3f41 Linus Torvalds 2005-04-16 9577 { e804ac780e2f01 Tejun Heo 2010-10-15 9578 int ret = -ENOMEM; e804ac780e2f01 Tejun Heo 2010-10-15 9579 ada609ee2ac2e0 Tejun Heo 2011-01-25 9580 md_wq = alloc_workqueue("md", WQ_MEM_RECLAIM, 0); e804ac780e2f01 Tejun Heo 2010-10-15 9581 if (!md_wq) e804ac780e2f01 Tejun Heo 2010-10-15 9582 goto err_wq; e804ac780e2f01 Tejun Heo 2010-10-15 9583 e804ac780e2f01 Tejun Heo 2010-10-15 9584 md_misc_wq = alloc_workqueue("md_misc", 0, 0); e804ac780e2f01 Tejun Heo 2010-10-15 9585 if (!md_misc_wq) e804ac780e2f01 Tejun Heo 2010-10-15 9586 goto err_misc_wq; e804ac780e2f01 Tejun Heo 2010-10-15 9587 cc1ffe61c026e2 Guoqing Jiang 2020-04-04 9588 md_rdev_misc_wq = alloc_workqueue("md_rdev_misc", 0, 0); cf0b9b4821a295 Guoqing Jiang 2020-10-08 9589 if (!md_rdev_misc_wq) cc1ffe61c026e2 Guoqing Jiang 2020-04-04 9590 goto err_rdev_misc_wq; cc1ffe61c026e2 Guoqing Jiang 2020-04-04 9591 28144f9998e047 Christoph Hellwig 2020-10-29 @9592 ret = __register_blkdev(MD_MAJOR, "md", md_probe); 28144f9998e047 Christoph Hellwig 2020-10-29 9593 if (ret < 0) e804ac780e2f01 Tejun Heo 2010-10-15 9594 goto err_md; e804ac780e2f01 Tejun Heo 2010-10-15 9595 28144f9998e047 Christoph Hellwig 2020-10-29 9596 ret = __register_blkdev(0, "mdp", md_probe); 28144f9998e047 Christoph Hellwig 2020-10-29 9597 if (ret < 0) e804ac780e2f01 Tejun Heo 2010-10-15 9598 goto err_mdp; e804ac780e2f01 Tejun Heo 2010-10-15 9599 mdp_major = ret; e804ac780e2f01 Tejun Heo 2010-10-15 9600 ^1da177e4c3f41 Linus Torvalds 2005-04-16 9601 register_reboot_notifier(&md_notifier); 0b4d414714f0d2 Eric W. Biederman 2007-02-14 9602 raid_table_header = register_sysctl_table(raid_root_table); ^1da177e4c3f41 Linus Torvalds 2005-04-16 9603 ^1da177e4c3f41 Linus Torvalds 2005-04-16 9604 md_geninit(); d710e138126000 NeilBrown 2008-10-13 9605 return 0; ^1da177e4c3f41 Linus Torvalds 2005-04-16 9606 e804ac780e2f01 Tejun Heo 2010-10-15 9607 err_mdp: e804ac780e2f01 Tejun Heo 2010-10-15 9608 unregister_blkdev(MD_MAJOR, "md"); e804ac780e2f01 Tejun Heo 2010-10-15 9609 err_md: cc1ffe61c026e2 Guoqing Jiang 2020-04-04 9610 destroy_workqueue(md_rdev_misc_wq); cc1ffe61c026e2 Guoqing Jiang 2020-04-04 9611 err_rdev_misc_wq: e804ac780e2f01 Tejun Heo 2010-10-15 9612 destroy_workqueue(md_misc_wq); e804ac780e2f01 Tejun Heo 2010-10-15 9613 err_misc_wq: e804ac780e2f01 Tejun Heo 2010-10-15 9614 destroy_workqueue(md_wq); e804ac780e2f01 Tejun Heo 2010-10-15 9615 err_wq: e804ac780e2f01 Tejun Heo 2010-10-15 9616 return ret; e804ac780e2f01 Tejun Heo 2010-10-15 9617 } ^1da177e4c3f41 Linus Torvalds 2005-04-16 9618 :::::: The code at line 9592 was first introduced by commit :::::: 28144f9998e047a9bac31421914335c6bc6eaa67 md: use __register_blkdev to allocate devices on demand :::::: TO: Christoph Hellwig <hch(a)lst.de&gt; :::::: CC: Jens Axboe <axboe(a)kernel.dk&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org