I want to create a program that logs a message when net_ns_net_exit function in the kernel is called.
SEC("fexit/net_ns_net_exit")
int BPF_PROG(net_ns_net_exit, struct net *net, long ret)
#endif
{
__u64 netns_inum = BPF_CORE_READ(net, ns.inum);
debugf("removing: netns_inum: %u", netns_inum);
return 0;
}
bpftool v7.0.0
using libbpf v1.0
features: libbfd, libbpf_strict, skeletons
I am building in on Ubuntu 22.04 with kernel 5.15.0-52-generic, AMD. The program works well on this machine, but when I try to run it on GCP with kernel version 5.10.133+ it fails with error:
libbpf: failed to find kernel BTF type ID of 'net_ns_net_exit': -3
libbpf: prog 'net_ns_net_exit': failed to prepare load attributes: -3
libbpf: prog 'net_ns_net_exit': failed to load: -3
libbpf: failed to load object 'remove_net_ns'
libbpf: failed to load BPF skeleton 'remove_net_ns': -3
loading remove_net_ns skeleton failed with error: -3
I've checked if vmlinux is available on machines and I found that both: GCP and my local ubuntu have: /sys/kernel/btf/vmlinux. I've checked the content(with vim) on the VM and I've noticed that my VM has net_ns_net_exit but GCP doesn't. I am not sure if it's related and how exactly make it works. Method: net_ns_net_exit was introduced to the kernel a long time ago so I've expected that it should be available. Maybe someone had this problem and has some advice or knows how to approach this issue?
