On Thu, Jun 15, 2023 at 09:47:24AM +0800, Yu Kuai wrote: > Hi, > > 在 2023/06/14 20:32, kernel test robot 写道: > > tree: git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git md-next > > head: 460af1f9d9e62acce4a21f9bd00b5bcd5963bcd4 > > commit: 8295efbe68c080047e98d9c0eb5cb933b238a8cb [25/29] md/raid1-10: factor out a helper to submit normal write > > config: arm-randconfig-r026-20230612 (https://download.01.org/0day-ci/archive/20230614/202306142042.fmjfmTF8-lkp@xxxxxxxxx/config) > > compiler: clang version 17.0.0 (https://github.com/llvm/llvm-project.git 4a5ac14ee968ff0ad5d2cc1ffa0299048db4c88a) > > reproduce (this is a W=1 build): > > mkdir -p ~/bin > > 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/song/md.git/commit/?id=8295efbe68c080047e98d9c0eb5cb933b238a8cb > > git remote add song-md git://git.kernel.org/pub/scm/linux/kernel/git/song/md.git > > git fetch --no-tags song-md md-next > > git checkout 8295efbe68c080047e98d9c0eb5cb933b238a8cb > > # save the config file > > mkdir build_dir && cp config build_dir/.config > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=arm olddefconfig > > COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang ~/bin/make.cross W=1 O=build_dir ARCH=arm SHELL=/bin/bash drivers/ > > > > If you fix the issue in a separate patch/commit (i.e. not just a new version of > > the same patch/commit), kindly add following tags > > | Reported-by: kernel test robot <lkp@xxxxxxxxx> > > | Closes: https://lore.kernel.org/oe-kbuild-all/202306142042.fmjfmTF8-lkp@xxxxxxxxx/ > > > > All errors (new ones prefixed by >>): > > > > In file included from drivers/md/raid10.c:80: > > > > drivers/md/raid1-10.c:117:25: error: casting from randomized structure pointer type 'struct block_device *' to 'struct md_rdev *' > > 117 | struct md_rdev *rdev = (struct md_rdev *)bio->bi_bdev; > > I didn't hit this warning with W=1 in my local machine, so I guess this > might related to compiler. I'm using gcc (GCC) 12.2.1 and here is clang > version 17.0.0. Interesting, I would have expected the GCC plugin to have the same behavior as clang (which has randstruct in the compiler proper) and error when casting randomized structures but I just tested with aarch64-linux-gnu-gcc (GCC) 13.1.0 and drivers/md/raid10.c builds just fine, so confirmed. For the record, this is a hard error, not a warning, so the build is broken in -next because of this: https://github.com/ClangBuiltLinux/continuous-integration2/actions/runs/5278732212/jobs/9552208141 > I'm planning to get rid of all these weird usage, which is used a lot in > raid, to borrow a field to store something else temporarily, but this > might take sometime. > > Can someone help to confirm following change can prevent this warning? > > struct md_rdev *rdev = (void *)bio->bi_bdev Yes, this fixes the build. In the future, if you need to reproduce issues with clang, I have prebuilt versions of stable clang/LLVM available on kernel.org: https://mirrors.edge.kernel.org/pub/tools/llvm/ Cheers, Nathan > > | ^ > > 1 error generated. > > > > > > vim +117 drivers/md/raid1-10.c > > > > 113 > > 114 > > 115 static inline void raid1_submit_write(struct bio *bio) > > 116 { > > > 117 struct md_rdev *rdev = (struct md_rdev *)bio->bi_bdev; > > 118 > > 119 bio->bi_next = NULL; > > 120 bio_set_dev(bio, rdev->bdev); > > 121 if (test_bit(Faulty, &rdev->flags)) > > 122 bio_io_error(bio); > > 123 else if (unlikely(bio_op(bio) == REQ_OP_DISCARD && > > 124 !bdev_max_discard_sectors(bio->bi_bdev))) > > 125 /* Just ignore it */ > > 126 bio_endio(bio); > > 127 else > > 128 submit_bio_noacct(bio); > > 129 } > > 130 > > > >
