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>>>>> + >>>>> + new_batch = kvmalloc(sizeof(*new_batch) * new_batch_sz, GFP_USER); >>>> >>>> Since we return -ENOMEM below, should we have __GFP_NOWARN in kvmalloc >>>> flags? >>> will add in v2. >>> >>>> >>>>> + if (!new_batch) >>>>> + return -ENOMEM; >>>>> + >>>>> + bpf_iter_tcp_put_batch(iter); >>>>> + kvfree(iter->batch); >>>>> + iter->batch = new_batch; >>>>> + iter->max_sk = new_batch_sz; >>>>> + >>>>> + return 0; >>>>> +} >>>>> + >>>> [...] >>>>> + >>>>> static int bpf_iter_tcp_seq_show(struct seq_file *seq, void *v) >>>>> { >>>>> struct bpf_iter_meta meta; >>>>> struct bpf_prog *prog; >>>>> struct sock *sk = v; >>>>> + bool slow; >>>>> uid_t uid; >>>>> + int ret; >>>>> if (v == SEQ_START_TOKEN) >>>>> return 0; >>>>> + if (sk_fullsock(sk)) >>>>> + slow = lock_sock_fast(sk); >>>>> + >>>>> + if (unlikely(sk_unhashed(sk))) { >>>>> + ret = SEQ_SKIP; >>>>> + goto unlock; >>>>> + } >>>> >>>> I am not a tcp expert. Maybe a dummy question. >>>> Is it possible to do setsockopt() for listening socket? >>>> What will happen if the listening sock is unhashed after the >>>> above check? >>> It won't happen because the sk has been locked before doing the >>> unhashed check. >> >> Ya, that is true. I guess I probably mean TCP_TIME_WAIT and >> TCP_NEW_SYN_RECV sockets. We cannot do setsockopt() for >> TCP_TIME_WAIT sockets since user space shouldn't be able >> to access the socket any more. >> >> But how about TCP_NEW_SYN_RECV sockets? > _bpf_setsockopt() will return -EINVAL for non fullsock. That makes sense. I think whether we could block calling bpf_setsockopt() for unsupported sockets outside bpf program. But indeed letting bpf to do filtering in such cases should be simpler.