tree: https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master head: 9317f948b0b188b8d2fded75957e6d42c460df1b commit: bd06731ef42b0b0fb321a06c182ffd83029f69f5 [12693/13311] ubsan: enable for all*config builds config: powerpc-randconfig-r006-20201216 (attached as .config) compiler: clang version 12.0.0 (https://github.com/llvm/llvm-project a29ecca7819a6ed4250d3689b12b1f664bb790d7) 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/next/linux-next.git/commi... git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git git fetch --no-tags linux-next master git checkout bd06731ef42b0b0fb321a06c182ffd83029f69f5 # 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 warnings (new ones prefixed by >>): void blake2s_compress_generic(struct blake2s_state *state,const u8 *block, ^ 1 warning generated. vim +/blake2s_compress_generic +40 lib/crypto/blake2s-generic.c 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 39 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 @40 void blake2s_compress_generic(struct blake2s_state *state,const u8 *block, 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 41 size_t nblocks, const u32 inc) 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 42 { 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 43 u32 m[16]; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 44 u32 v[16]; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 45 int i; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 46 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 47 WARN_ON(IS_ENABLED(DEBUG) && 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 48 (nblocks > 1 && inc != BLAKE2S_BLOCK_SIZE)); 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 49 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 50 while (nblocks > 0) { 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 51 blake2s_increment_counter(state, inc); 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 52 memcpy(m, block, BLAKE2S_BLOCK_SIZE); 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 53 le32_to_cpu_array(m, ARRAY_SIZE(m)); 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 54 memcpy(v, state->h, 32); 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 55 v[ 8] = BLAKE2S_IV0; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 56 v[ 9] = BLAKE2S_IV1; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 57 v[10] = BLAKE2S_IV2; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 58 v[11] = BLAKE2S_IV3; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 59 v[12] = BLAKE2S_IV4 ^ state->t[0]; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 60 v[13] = BLAKE2S_IV5 ^ state->t[1]; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 61 v[14] = BLAKE2S_IV6 ^ state->f[0]; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 62 v[15] = BLAKE2S_IV7 ^ state->f[1]; 66d7fb94e4ffe5a Jason A. Donenfeld 2019-11-08 63 :::::: The code at line 40 was first introduced by commit :::::: 66d7fb94e4ffe5acc589e0b2b4710aecc1f07a28 crypto: blake2s - generic C library implementation and selftest :::::: TO: Jason A. Donenfeld <Jason(a)zx2c4.com&gt; :::::: CC: Herbert Xu <herbert(a)gondor.apana.org.au&gt; --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org