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(-)
--
2.43.0
