On 6/22/19 6:27 AM, Stanislav Fomichev wrote:
On 06/21, Andrii Nakryiko wrote:
)
On Fri, Jun 21, 2019 at 9:11 AM Stanislav Fomichev <s...@fomichev.me> 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.c...@intel.com>
# 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 :-(
Thanks for the clarification, we'll upgrade clang asap.
Best Regards,
Rong Chen
# 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>
