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 kernel? It makes no sense to limit attaching to a proper kallsym symbol. > tools/lib/bpf/libbpf.c | 9 ++++++++- > tools/lib/bpf/libbpf.h | 4 +++- > 2 files changed, 11 insertions(+), 2 deletions(-) > [...]
