On Tue, Jun 29, 2021 at 10:27:17AM -0700, Yonghong Song wrote:
[ ... ]
> > +static int bpf_iter_tcp_realloc_batch(struct bpf_tcp_iter_state *iter,
> > + unsigned int new_batch_sz)
> > +{
> > + struct sock **new_batch;
> > +
> > + 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.
Thanks for the review.
