Hi Sven, [auto build test ERROR on linus/master] [also build test ERROR on v4.10-rc4 next-20170120] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/Sven-Schmidt/Update-LZ4-compressor-module/20170121-231418 config: i386-randconfig-r0-201703 (attached as .config) compiler: gcc-5 (Debian 5.4.1-2) 5.4.1 20160904 reproduce: # save the attached .config to linux build tree make ARCH=i386 Note: the linux-review/Sven-Schmidt/Update-LZ4-compressor-module/20170121-231418 HEAD 0472409e2a1c442b51502961aa6d83b866218953 builds fine. It only hurts bisectibility. All errors (new ones prefixed by >>): fs/pstore/platform.c: In function 'allocate_lz4': >> fs/pstore/platform.c:369:20: error: implicit declaration of function 'lz4_compressbound' [-Werror=implicit-function-declaration] big_oops_buf_sz = lz4_compressbound(psinfo->bufsize); ^ cc1: some warnings being treated as errors vim +/lz4_compressbound +369 fs/pstore/platform.c 8cfc8ddc Geliang Tang 2016-02-18 363 8cfc8ddc Geliang Tang 2016-02-18 364 return outlen; 8cfc8ddc Geliang Tang 2016-02-18 365 } 8cfc8ddc Geliang Tang 2016-02-18 366 8cfc8ddc Geliang Tang 2016-02-18 367 static void allocate_lz4(void) 8cfc8ddc Geliang Tang 2016-02-18 368 { 8cfc8ddc Geliang Tang 2016-02-18 @369 big_oops_buf_sz = lz4_compressbound(psinfo->bufsize); 8cfc8ddc Geliang Tang 2016-02-18 370 big_oops_buf = kmalloc(big_oops_buf_sz, GFP_KERNEL); 8cfc8ddc Geliang Tang 2016-02-18 371 if (big_oops_buf) { 8cfc8ddc Geliang Tang 2016-02-18 372 workspace = kmalloc(LZ4_MEM_COMPRESS, GFP_KERNEL); :::::: The code at line 369 was first introduced by commit :::::: 8cfc8ddc99df9509a46043b14af81f5c6a223eab pstore: add lzo/lz4 compression support :::::: TO: Geliang Tang :::::: CC: Kees Cook --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation