Hello, Andrii On 2022/3/30 7:18 AM, Andrii Nakryiko wrote: > On Sat, Mar 26, 2022 at 7:43 AM Hengqi Chen <hengqi.chen@xxxxxxxxx> wrote: >> >> On some old kernels, kprobe auto-attach may fail when attach to symbols >> like udp_send_skb.isra.52 . This is because the kernel has kprobe PMU >> but don't allow attach to a symbol with '.' ([0]). Add a new option to >> bpf_kprobe_opts to allow using the legacy kprobe attach directly. >> This way, users can use bpf_program__attach_kprobe_opts in a dedicated >> custom sec handler to handle such case. >> >> [0]: https://github.com/torvalds/linux/blob/v4.18/kernel/trace/trace_kprobe.c#L340-L343 >> >> Signed-off-by: Hengqi Chen <hengqi.chen@xxxxxxxxx> >> --- > > It's sad, but it makes sense. But, let's have a selftests that > validates uses legacy option explicitly (e.g., in > prog_tests/attach_probe.c). Also, let's fix this limitation in the OK, will add a selftest to exercise the new option. > kernel? It makes no sense to limit attaching to a proper kallsym > symbol. This limitation is lifted in newer kernel. Kernel v5.4 don't have this issue. > >> tools/lib/bpf/libbpf.c | 9 ++++++++- >> tools/lib/bpf/libbpf.h | 4 +++- >> 2 files changed, 11 insertions(+), 2 deletions(-) >> > > [...] -- Hengqi
