Hi Ard, I love your patch! Perhaps something to improve: [auto build test WARNING on herbert-cryptodev-2.6/master] [also build test WARNING on herbert-crypto-2.6/master v5.17-rc4 next-20220215] [If your patch is applied to the wrong git tree, kindly drop us a note. And when submitting patch, we suggest to use '--base' as documented in https://git-scm.com/docs/git-format-patch] url: https://github.com/0day-ci/linux/commits/Ard-Biesheuvel/crypto-crypto_xor... base: https://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git master config: arc-allyesconfig (https://download.01.org/0day-ci/archive/20220215/202202152134.HZ9sQwkL-lk...) compiler: arceb-elf-gcc (GCC) 11.2.0 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://github.com/0day-ci/linux/commit/6ca2d09816a67230ab30f3c7e7d87815e... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Ard-Biesheuvel/crypto-crypto_xor-use-helpers-for-unaligned-accesses/20220215-185741 git checkout 6ca2d09816a67230ab30f3c7e7d87815e833d0af # save the config file to linux build tree mkdir build_dir COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=arc SHELL=/bin/bash drivers/md/ 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 >>): In file included from arch/arc/include/asm/unaligned.h:11, from arch/arc/include/asm/io.h:12, from include/linux/io.h:13, from include/linux/irq.h:20, from include/asm-generic/hardirq.h:17, from ./arch/arc/include/generated/asm/hardirq.h:1, from include/linux/hardirq.h:11, from include/linux/highmem.h:11, from include/linux/bvec.h:10, from include/linux/blk_types.h:10, from include/linux/bio.h:10, from drivers/md/dm-crypt.c:16: In function 'crypto_xor_cpy', inlined from 'crypt_iv_tcw_whitening.isra' at drivers/md/dm-crypt.c:645:2: 14 | __pptr->x; \ | ~~~~~~^~~ include/asm-generic/unaligned.h:22:33: note: in expansion of macro '__get_unaligned_t' 22 | #define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr)) | ^~~~~~~~~~~~~~~~~ include/crypto/algapi.h:183:29: note: in expansion of macro 'get_unaligned' 183 | l = get_unaligned(d) ^ get_unaligned(s1++) | ^~~~~~~~~~~~~ drivers/md/dm-crypt.c: In function 'crypt_iv_tcw_whitening.isra': drivers/md/dm-crypt.c:640:12: note: 'buf' declared here 640 | u8 buf[TCW_WHITENING_SIZE]; | ^~~ In file included from arch/arc/include/asm/unaligned.h:11, from arch/arc/include/asm/io.h:12, from include/linux/io.h:13, from include/linux/irq.h:20, from include/asm-generic/hardirq.h:17, from ./arch/arc/include/generated/asm/hardirq.h:1, from include/linux/hardirq.h:11, from include/linux/highmem.h:11, from include/linux/bvec.h:10, from include/linux/blk_types.h:10, from include/linux/bio.h:10, from drivers/md/dm-crypt.c:16: In function 'crypto_xor_cpy', inlined from 'crypt_iv_tcw_whitening.isra' at drivers/md/dm-crypt.c:645:2: include/asm-generic/unaligned.h:14:15: warning: '*(const struct <anonymous> *)(&buf[4]).x' is used uninitialized [-Wuninitialized] 14 | __pptr->x; \ | ~~~~~~^~~ include/asm-generic/unaligned.h:22:33: note: in expansion of macro '__get_unaligned_t' 22 | #define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr)) | ^~~~~~~~~~~~~~~~~ include/crypto/algapi.h:183:29: note: in expansion of macro 'get_unaligned' 183 | l = get_unaligned(d) ^ get_unaligned(s1++) | ^~~~~~~~~~~~~ drivers/md/dm-crypt.c: In function 'crypt_iv_tcw_whitening.isra': drivers/md/dm-crypt.c:640:12: note: 'buf' declared here 640 | u8 buf[TCW_WHITENING_SIZE]; | ^~~ In file included from arch/arc/include/asm/unaligned.h:11, from arch/arc/include/asm/io.h:12, from include/linux/io.h:13, from include/linux/irq.h:20, from include/asm-generic/hardirq.h:17, from ./arch/arc/include/generated/asm/hardirq.h:1, from include/linux/hardirq.h:11, from include/linux/highmem.h:11, from include/linux/bvec.h:10, from include/linux/blk_types.h:10, from include/linux/bio.h:10, from drivers/md/dm-crypt.c:16: In function 'crypto_xor_cpy', inlined from 'crypt_iv_tcw_whitening.isra' at drivers/md/dm-crypt.c:646:2: include/asm-generic/unaligned.h:14:15: warning: '*(const struct <anonymous> *)(&buf[8]).x' is used uninitialized [-Wuninitialized] 14 | __pptr->x; \ | ~~~~~~^~~ include/asm-generic/unaligned.h:22:33: note: in expansion of macro '__get_unaligned_t' 22 | #define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr)) | ^~~~~~~~~~~~~~~~~ include/crypto/algapi.h:183:29: note: in expansion of macro 'get_unaligned' 183 | l = get_unaligned(d) ^ get_unaligned(s1++) | ^~~~~~~~~~~~~ drivers/md/dm-crypt.c: In function 'crypt_iv_tcw_whitening.isra': drivers/md/dm-crypt.c:640:12: note: 'buf' declared here 640 | u8 buf[TCW_WHITENING_SIZE]; | ^~~ In file included from arch/arc/include/asm/unaligned.h:11, from arch/arc/include/asm/io.h:12, from include/linux/io.h:13, from include/linux/irq.h:20, from include/asm-generic/hardirq.h:17, from ./arch/arc/include/generated/asm/hardirq.h:1, from include/linux/hardirq.h:11, from include/linux/highmem.h:11, from include/linux/bvec.h:10, from include/linux/blk_types.h:10, from include/linux/bio.h:10, from drivers/md/dm-crypt.c:16: In function 'crypto_xor_cpy', inlined from 'crypt_iv_tcw_whitening.isra' at drivers/md/dm-crypt.c:646:2: include/asm-generic/unaligned.h:14:15: warning: '*(const struct <anonymous> *)(&buf[12]).x' is used uninitialized [-Wuninitialized] 14 | __pptr->x; \ | ~~~~~~^~~ include/asm-generic/unaligned.h:22:33: note: in expansion of macro '__get_unaligned_t' 22 | #define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr)) | ^~~~~~~~~~~~~~~~~ include/crypto/algapi.h:183:29: note: in expansion of macro 'get_unaligned' 183 | l = get_unaligned(d) ^ get_unaligned(s1++) | ^~~~~~~~~~~~~ drivers/md/dm-crypt.c: In function 'crypt_iv_tcw_whitening.isra': drivers/md/dm-crypt.c:640:12: note: 'buf' declared here 640 | u8 buf[TCW_WHITENING_SIZE]; | ^~~ vim +14 include/asm-generic/unaligned.h aafe4dbed0bf6c Arnd Bergmann 2009-05-13 11 803f4e1eab7a89 Arnd Bergmann 2021-05-08 12 #define __get_unaligned_t(type, ptr) ({ \ 803f4e1eab7a89 Arnd Bergmann 2021-05-08 13 const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ 803f4e1eab7a89 Arnd Bergmann 2021-05-08 @14 __pptr->x; \ 803f4e1eab7a89 Arnd Bergmann 2021-05-08 15 }) 803f4e1eab7a89 Arnd Bergmann 2021-05-08 16 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org