On Mon, Oct 21, 2019 at 10:07:59PM -0700, John Fastabend wrote: > Andrii Nakryiko wrote: > > On Sat, Oct 19, 2019 at 1:30 AM John Fastabend <john.fastabend@xxxxxxxxx> wrote: > > > > > > Following ./Documentation/trace/kprobetrace.rst add support for loading > > > kprobes programs on older kernels. > > > > My main concern with this is that this code is born bit-rotten, > > because selftests are never testing the legacy code path. How did you > > think about testing this and ensuring that this keeps working going > > forward? > > Well we use it, but I see your point and actually I even broke the retprobe > piece hastily fixing merge conflicts in this patch. When I ran tests on it > I missed running retprobe tests on the set of kernels that would hit that > code. If it also gets explicitly exposed as bpf_program__attach_legacy_kprobe() or such, it should be easy to add BPF selftests for that API to address the test coverage concern. Generally more selftests for exposed libbpf APIs is good to have anyway. Cheers, Daniel
