Hi Alexei, FYI, the error/warning still remains. tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master head: c605c39677b9842b0566013e0cf30bc13e90bdbc commit: d71fa5c9763c24dd997a2fa4feb7a13a95bab42c bpf: Add kernel module with user mode driver that populates bpffs. date: 1 year, 1 month ago config: i386-randconfig-a013-20210910 (attached as .config) compiler: gcc-9 (Debian 9.3.0-22) 9.3.0 reproduce (this is a W=1 build): # https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=d71fa5c9763c24dd997a2fa4feb7a13a95bab42c git remote add linus https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git git fetch --no-tags linus master git checkout d71fa5c9763c24dd997a2fa4feb7a13a95bab42c # save the attached .config to linux build tree mkdir build_dir make W=1 O=build_dir ARCH=i386 SHELL=/bin/bash If you fix the issue, kindly add following tag as appropriate Reported-by: kernel test robot All errors (new ones prefixed by >>): /usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libelf.so when searching for -lelf /usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libelf.a when searching for -lelf /usr/bin/ld: cannot find -lelf /usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libelf.so when searching for -lelf /usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libz.so when searching for -lz /usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libz.a when searching for -lz /usr/bin/ld: cannot find -lz /usr/bin/ld: skipping incompatible /usr/lib/x86_64-linux-gnu/libz.so when searching for -lz >> collect2: error: ld returned 1 exit status --- 0-DAY CI Kernel Test Service, Intel Corporation https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org