Hi Ard, First bad commit (maybe != root cause): tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: eb5f95f1593f7c22dac681b19e815828e2af3efd commit: 5fb8ef25803ef33e2eb60b626435828b937bed75 crypto: chacha - move existing library code into lib/crypto date: 10 months ago config: i386-randconfig-r012-20200920 (attached as .config) compiler: gcc-9 (Debian 9.3.0-15) 9.3.0 reproduce (this is a W=1 build): git checkout 5fb8ef25803ef33e2eb60b626435828b937bed75 # save the attached .config to linux build tree make W=1 ARCH=i386 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 >>): lib/crypto/chacha.c: In function 'chacha_permute': 65 | } | ^ # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit... git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout 5fb8ef25803ef33e2eb60b626435828b937bed75 vim +65 lib/crypto/chacha.c e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 16 1ca1b917940c24 lib/chacha.c Eric Biggers 2018-11-16 17 static void chacha_permute(u32 *x, int nrounds) e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 18 { e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 19 int i; e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 20 1ca1b917940c24 lib/chacha.c Eric Biggers 2018-11-16 21 /* whitelist the allowed round counts */ aa7624093cb7fb lib/chacha.c Eric Biggers 2018-11-16 22 WARN_ON_ONCE(nrounds != 20 && nrounds != 12); 1ca1b917940c24 lib/chacha.c Eric Biggers 2018-11-16 23 1ca1b917940c24 lib/chacha.c Eric Biggers 2018-11-16 24 for (i = 0; i < nrounds; i += 2) { 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 25 x[0] += x[4]; x[12] = rol32(x[12] ^ x[0], 16); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 26 x[1] += x[5]; x[13] = rol32(x[13] ^ x[1], 16); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 27 x[2] += x[6]; x[14] = rol32(x[14] ^ x[2], 16); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 28 x[3] += x[7]; x[15] = rol32(x[15] ^ x[3], 16); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 29 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 30 x[8] += x[12]; x[4] = rol32(x[4] ^ x[8], 12); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 31 x[9] += x[13]; x[5] = rol32(x[5] ^ x[9], 12); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 32 x[10] += x[14]; x[6] = rol32(x[6] ^ x[10], 12); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 33 x[11] += x[15]; x[7] = rol32(x[7] ^ x[11], 12); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 34 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 35 x[0] += x[4]; x[12] = rol32(x[12] ^ x[0], 8); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 36 x[1] += x[5]; x[13] = rol32(x[13] ^ x[1], 8); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 37 x[2] += x[6]; x[14] = rol32(x[14] ^ x[2], 8); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 38 x[3] += x[7]; x[15] = rol32(x[15] ^ x[3], 8); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 39 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 40 x[8] += x[12]; x[4] = rol32(x[4] ^ x[8], 7); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 41 x[9] += x[13]; x[5] = rol32(x[5] ^ x[9], 7); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 42 x[10] += x[14]; x[6] = rol32(x[6] ^ x[10], 7); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 43 x[11] += x[15]; x[7] = rol32(x[7] ^ x[11], 7); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 44 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 45 x[0] += x[5]; x[15] = rol32(x[15] ^ x[0], 16); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 46 x[1] += x[6]; x[12] = rol32(x[12] ^ x[1], 16); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 47 x[2] += x[7]; x[13] = rol32(x[13] ^ x[2], 16); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 48 x[3] += x[4]; x[14] = rol32(x[14] ^ x[3], 16); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 49 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 50 x[10] += x[15]; x[5] = rol32(x[5] ^ x[10], 12); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 51 x[11] += x[12]; x[6] = rol32(x[6] ^ x[11], 12); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 52 x[8] += x[13]; x[7] = rol32(x[7] ^ x[8], 12); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 53 x[9] += x[14]; x[4] = rol32(x[4] ^ x[9], 12); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 54 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 55 x[0] += x[5]; x[15] = rol32(x[15] ^ x[0], 8); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 56 x[1] += x[6]; x[12] = rol32(x[12] ^ x[1], 8); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 57 x[2] += x[7]; x[13] = rol32(x[13] ^ x[2], 8); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 58 x[3] += x[4]; x[14] = rol32(x[14] ^ x[3], 8); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 59 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 60 x[10] += x[15]; x[5] = rol32(x[5] ^ x[10], 7); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 61 x[11] += x[12]; x[6] = rol32(x[6] ^ x[11], 7); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 62 x[8] += x[13]; x[7] = rol32(x[7] ^ x[8], 7); 7660b1fb367eb3 lib/chacha20.c Eric Biggers 2017-12-31 63 x[9] += x[14]; x[4] = rol32(x[4] ^ x[9], 7); e192be9d9a3055 lib/chacha20.c Theodore Ts'o 2016-06-12 64 } dd333449d0fb66 lib/chacha20.c Eric Biggers 2018-11-16 @65 } dd333449d0fb66 lib/chacha20.c Eric Biggers 2018-11-16 66 :::::: The code at line 65 was first introduced by commit :::::: dd333449d0fb667c5250c42488a7e90470e16c77 crypto: chacha20-generic - add HChaCha20 library function :::::: TO: Eric Biggers <ebiggers(a)google.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