On 06/21, Andrii Nakryiko wrote: > ) > > On Fri, Jun 21, 2019 at 9:11 AM Stanislav Fomichev <sdf(a)fomichev.me&gt; wrote: >> On 06/21, kernel test robot wrote: >>> FYI, we noticed the following commit (built with gcc-7): >>> >>> commit: 69d96519dbf0bfa1868dc8597d4b9b2cdeb009d7 ("selftests/bpf: convert socket_cookie test to sk storage") >>> https://git.kernel.org/cgit/linux/kernel/git/next/linux-next.git master >>> >>> in testcase: kernel_selftests >>> with following parameters: >>> >>> group: kselftests-00 >>> >>> test-description: The kernel contains a set of "self tests" under the tools/testing/selftests/ directory. These are intended to be small unit tests to exercise individual code paths in the kernel. >>> test-url: https://www.kernel.org/doc/Documentation/kselftest.txt >>> >>> >>> on test machine: qemu-system-x86_64 -enable-kvm -cpu SandyBridge -smp 2 -m 4G >>> >>> caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): >>> >>> >>> If you fix the issue, kindly add following tag >>> Reported-by: kernel test robot <rong.a.chen(a)intel.com&gt; >>> >>> # selftests: bpf: test_socket_cookie >>> # libbpf: failed to create map (name: 'socket_cookies'): Invalid >>> # argument >> Another case of old clang trying to create a map that depends on BTF? >> Should we maybe switch those BTF checks in the kernel to return >> EOPNOTSUPP to make it easy to diagnose? > For older compilers that don't generate DATASEC/VAR, you'll see a clear message: > > libbpf: DATASEC '.maps' not found. > > So this must be something else. I just confirmed with clang version > 7.0.20180201 that for ./test_socket_cookie that's the first line > that's emitted on failure. Thanks for checking, I also took a look at the attached kernel_selftests.xz, here is what it has: 2019-06-21 11:58:35 ln -sf /usr/bin/clang-6.0 /usr/bin/clang 2019-06-21 11:58:35 ln -sf /usr/bin/llc-6.0 /usr/bin/llc ... # BTF libbpf test[1] (test_btf_haskv.o): SKIP. No ELF .BTF found # BTF libbpf test[2] (test_btf_nokv.o): SKIP. No ELF .BTF found ... # Test case #0 (btf_dump_test_case_syntax): test_btf_dump_case:71:FAIL # failed to load test BTF: -2 # Test case #1 (btf_dump_test_case_ordering): test_btf_dump_case:71:FAIL # failed to load test BTF: -2 ... And so on. So there is clearly an old clang that doesn't emit any BTF. And I also don't see your recent abd29c931459 before 69d96519dbf0 in linux-next, that's why it doesn't complain about missing/corrupt BTF. We need to convince lkp people to upgrade clang, otherwise, I suppose, we'll get more of these reportings after your recent df0b77925982 :-(

>>> # libbpf: failed to load object './socket_cookie_prog.o' >>> # (test_socket_cookie.c:149: errno: Invalid argument) Failed to load >>> # ./socket_cookie_prog.o >>> # FAILED >>> not ok 15 selftests: bpf: test_socket_cookie >>> >>> >>> >>> >>> To reproduce: >>> >>> # build kernel >>> cd linux >>> cp config-5.2.0-rc2-00598-g69d9651 .config >>> make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 olddefconfig >>> make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 prepare >>> make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 modules_prepare >>> make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 SHELL=/bin/bash >>> make HOSTCC=gcc-7 CC=gcc-7 ARCH=x86_64 bzImage >>> >>> >>> git clone https://github.com/intel/lkp-tests.git >>> cd lkp-tests >>> bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email >>> >>> >>> >>> Thanks, >>> Rong Chen >>> > <mega snip>