As discovered by @Fabfur during the testing of https://gitlab.wikimedia.org/repos/sre/tcp-mss-clamper/-/merge_requests/10, tcp-mss-clamper doesn't work on bullseye (kernel 5.10) at the moment. eBPF program fails to load with the following error:
%!(EXTRA *fmt.wrapError=field TcpMssClamper: program tcp_mss_clamper: load program: invalid argument: number of funcs in func_info doesn't match number of subprogs (1 line(s) omitted)) 2023/12/18 16:01:15 Unable to init eBPF program: field TcpMssClamper: program tcp_mss_clamper: load program: invalid argument: number of funcs in func_info doesn't match number of subprogs (1 line(s) omitted)
This seems to be triggered by the usage of bpf_for_each_map_elem introduced on https://lwn.net/Articles/846504/ and that it isn't a part of the 5.10.x kernels