Hi "Jason, I love your patch! Perhaps something to improve: [auto build test WARNING on next-20220211] [cannot apply to char-misc/char-misc-testing linux/master linus/master v5.17-rc3 v5.17-rc2 v5.17-rc1 v5.17-rc3] [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/Jason-A-Donenfeld/random-do-not-... base: 6d9bd4ad4ca08b1114e814c2c42383b8b13be631 config: um-x86_64_defconfig (https://download.01.org/0day-ci/archive/20220212/202202121223.7CKs3pQ3-lk...) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://github.com/0day-ci/linux/commit/cac377f6ab22a8bfe966643ebe19812e8... git remote add linux-review https://github.com/0day-ci/linux git fetch --no-tags linux-review Jason-A-Donenfeld/random-do-not-take-pool-spinlock-at-boot/20220212-083131 git checkout cac377f6ab22a8bfe966643ebe19812e8187de3b # save the config file to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=um SUBARCH=x86_64 SHELL=/bin/bash drivers/char/ 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 >>): drivers/char/random.c: In function 'rand_initialize': drivers/char/random.c:162:3: error: implicit declaration of function '_mix_pool_bytes'; did you mean 'mix_pool_bytes'? [-Werror=implicit-function-declaration] 162 | _mix_pool_bytes(&rv, sizeof(rv)); | ^~~~~~~~~~~~~~~ | mix_pool_bytes drivers/char/random.c: At top level: 822 | static void _mix_pool_bytes(const void *in, size_t nbytes) | ^~~~~~~~~~~~~~~ drivers/char/random.c:822:13: error: static declaration of '_mix_pool_bytes' follows non-static declaration drivers/char/random.c:162:3: note: previous implicit declaration of '_mix_pool_bytes' was here 162 | _mix_pool_bytes(&rv, sizeof(rv)); | ^~~~~~~~~~~~~~~ drivers/char/random.c:1109:6: warning: no previous prototype for 'add_hwgenerator_randomness' [-Wmissing-prototypes] 1109 | void add_hwgenerator_randomness(const void *buffer, size_t count, | ^~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: some warnings being treated as errors vim +/_mix_pool_bytes +822 drivers/char/random.c b980955236922ae Theodore Ts'o 2013-03-04 821 b67959013391e48 Jason A. Donenfeld 2022-02-10 @822 static void _mix_pool_bytes(const void *in, size_t nbytes) b67959013391e48 Jason A. Donenfeld 2022-02-10 823 { b67959013391e48 Jason A. Donenfeld 2022-02-10 824 blake2s_update(&input_pool.hash, in, nbytes); ^1da177e4c3f415 Linus Torvalds 2005-04-16 825 } ^1da177e4c3f415 Linus Torvalds 2005-04-16 826 --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org