On Thu, Aug 16, 2018 at 12:49 PM, Daniel Borkmann <dan...@iogearbox.net> wrote:
> I found that in BPF sockmap programs once we either delete a socket
> from the map or we updated a map slot and the old socket was purged
> from the map that these socket can never get reattached into a map
> even though their related psock has been dropped entirely at that
> point.
>
> Reason is that tcp_cleanup_ulp() leaves the old icsk->icsk_ulp_ops
> intact, so that on the next tcp_set_ulp_id() the kernel returns an
> -EEXIST thinking there is still some active ULP attached.
>
> BPF sockmap is the only one that has this issue as the other user,
> kTLS, only calls tcp_cleanup_ulp() from tcp_v4_destroy_sock() whereas
> sockmap semantics allow dropping the socket from the map with all
> related psock state being cleaned up.
>
> Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks")
> Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
> Acked-by: John Fastabend <john.fastab...@gmail.com>Acked-by: Song Liu <songliubrav...@fb.com> > --- > net/ipv4/tcp_ulp.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c > index 7dd44b6..a5995bb 100644 > --- a/net/ipv4/tcp_ulp.c > +++ b/net/ipv4/tcp_ulp.c > @@ -129,6 +129,8 @@ void tcp_cleanup_ulp(struct sock *sk) > if (icsk->icsk_ulp_ops->release) > icsk->icsk_ulp_ops->release(sk); > module_put(icsk->icsk_ulp_ops->owner); > + > + icsk->icsk_ulp_ops = NULL; > } > > /* Change upper layer protocol for socket */ > -- > 2.9.5 >
