| Message ID | 20240326041443.1197498-1-yonghong.song@linux.dev (mailing list archive) |
|---|---|
| Headers | show |
| Series | bpf: Fix a couple of test failures with LTO kernel | expand |
Hello: This series was applied to bpf/bpf-next.git (master) by Alexei Starovoitov <ast@kernel.org>: On Mon, 25 Mar 2024 21:14:43 -0700 you wrote: > With a LTO kernel built with clang, with one of earlier version of kernel, > I encountered two test failures, ksyms and kprobe_multi_bench_attach/kernel. > Now with latest bpf-next, only kprobe_multi_bench_attach/kernel failed. > But it is possible in the future ksyms selftest may fail again. > > Both test failures are due to static variable/function renaming > due to cross-file inlining. For Ksyms failure, the solution is > to strip .llvm.<hash> suffixes for symbols in /proc/kallsyms before > comparing against the ksym in bpf program. > For kprobe_multi_bench_attach/kernel failure, the solution is > to either provide names in /proc/kallsyms to the kernel or > ignore those names who have .llvm.<hash> suffix since the kernel > sym name comparison is against /proc/kallsyms. > > [...] Here is the summary with links: - [bpf-next,v3,1/8] selftests/bpf: Replace CHECK with ASSERT macros for ksyms test https://git.kernel.org/bpf/bpf-next/c/779012842209 - [bpf-next,v3,2/8] libbpf: Mark libbpf_kallsyms_parse static function https://git.kernel.org/bpf/bpf-next/c/2c8bc4cf4d03 - [bpf-next,v3,3/8] libbpf: Handle <orig_name>.llvm.<hash> symbol properly https://git.kernel.org/bpf/bpf-next/c/afc6524702c5 - [bpf-next,v3,4/8] selftests/bpf: Refactor some functions for kprobe_multi_test https://git.kernel.org/bpf/bpf-next/c/de2c50ce88ec - [bpf-next,v3,5/8] selftests/bpf: Refactor trace helper func load_kallsyms_local() https://git.kernel.org/bpf/bpf-next/c/8cfdd77e94e6 - [bpf-next,v3,6/8] selftests/bpf: Add {load,search}_kallsyms_custom_local() https://git.kernel.org/bpf/bpf-next/c/3fa5b1626130 - [bpf-next,v3,7/8] selftests/bpf: Fix kprobe_multi_bench_attach test failure with LTO kernel https://git.kernel.org/bpf/bpf-next/c/ba4a347e17d0 - [bpf-next,v3,8/8] selftests/bpf: Add a kprobe_multi subtest to use addrs instead of syms https://git.kernel.org/bpf/bpf-next/c/aa17f462133f You are awesome, thank you!
With a LTO kernel built with clang, with one of earlier version of kernel, I encountered two test failures, ksyms and kprobe_multi_bench_attach/kernel. Now with latest bpf-next, only kprobe_multi_bench_attach/kernel failed. But it is possible in the future ksyms selftest may fail again. Both test failures are due to static variable/function renaming due to cross-file inlining. For Ksyms failure, the solution is to strip .llvm.<hash> suffixes for symbols in /proc/kallsyms before comparing against the ksym in bpf program. For kprobe_multi_bench_attach/kernel failure, the solution is to either provide names in /proc/kallsyms to the kernel or ignore those names who have .llvm.<hash> suffix since the kernel sym name comparison is against /proc/kallsyms. Please see each individual patches for details. Changelogs: v2 -> v3: - no need to check config file, directly so strstr with '.llvm.'. - for kprobe_multi_bench with syms, instead of skipping the syms, consult /proc/kallyms to find corresponding names. - add a test with populating addrs to the kernel for kprobe multi attach. v1 -> v2: - Let libbpf handle .llvm.<hash suffixes since it may impact bpf program ksym. Yonghong Song (8): selftests/bpf: Replace CHECK with ASSERT macros for ksyms test libbpf: Mark libbpf_kallsyms_parse static function libbpf: Handle <orig_name>.llvm.<hash> symbol properly selftests/bpf: Refactor some functions for kprobe_multi_test selftests/bpf: Refactor trace helper func load_kallsyms_local() selftests/bpf: Add {load,search}_kallsyms_custom_local() selftests/bpf: Fix kprobe_multi_bench_attach test failure with LTO kernel selftests/bpf: Add a kprobe_multi subtest to use addrs instead of syms tools/lib/bpf/libbpf.c | 26 +- tools/lib/bpf/libbpf_internal.h | 5 - .../bpf/prog_tests/kprobe_multi_test.c | 248 ++++++++++++++---- .../testing/selftests/bpf/prog_tests/ksyms.c | 30 +-- tools/testing/selftests/bpf/trace_helpers.c | 46 +++- tools/testing/selftests/bpf/trace_helpers.h | 7 + 6 files changed, 281 insertions(+), 81 deletions(-)