On 2026/3/11 23:44, Alexei Starovoitov wrote: > On Wed, Mar 11, 2026 at 2:22 AM Kumar Kartikeya Dwivedi > <[email protected]> wrote: >>
[...] >> >> I agree but the main question is whether such a case is realistic, are >> we going to have write_ctx programs tail calling this way? >> Tail calls are already pretty rare, thinking more about it extension >> programs are probably also broken wrt checks in this set. >> bpf_check_attach_target is doing none of these things for >> prog_extension = true. Nobody reported a problem, so I doubt anyone is >> hitting this. >> It probably also needs to be fixed. >> Since you noticed it, we should close the gap conservatively for now, >> and wait for a real use case to pop up before enabling this one-way. > > +1 > tail_calls in general hopefully will be deprecated soon. > As soon as we have support for indirect calls there won't be any reason > for tail calls to exist. (other than not breaking current users). > We definitely don't want to open it up further. > So the simplest fix. Got it. Will follow the both-ways check approach in the next revision. Will apply the conservative check to extension programs using another patch series, after verifying the potential issues for them. Thanks, Leon
