On Thu, 2015-07-30 at 04:55 -0400, Sowmini Varadhan wrote:
> The newsk returned by sk_clone_lock should hold a get_net()
> reference if, and only if, the parent is not a kernel socket
> (making this similar to sk_alloc()).
>
> E.g,. for the SYN_RECV call path, tcp_v4_syn_recv_sock->..inet_csk_clone_lock
> sets up the syn_recv newsk from sk_clone_lock. When the parent (listen)
> socket is a kernel socket (defined in sk_alloc() as having
> sk_net_refcnt == 0), then the newsk should also have a 0 sk_net_refcnt
> and should not hold a get_net() reference.
>
> Signed-off-by: Sowmini Varadhan <[email protected]>
> ---
> net/core/sock.c | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/net/core/sock.c b/net/core/sock.c
> index 08f16db..371d1b7 100644
> --- a/net/core/sock.c
> +++ b/net/core/sock.c
> @@ -1497,7 +1497,8 @@ struct sock *sk_clone_lock(const struct sock *sk, const
> gfp_t priority)
> sock_copy(newsk, sk);
>
> /* SANITY */
> - get_net(sock_net(newsk));
> + if (likely(newsk->sk_net_refcnt))
> + get_net(sock_net(newsk));
> sk_node_init(&newsk->sk_node);
> sock_lock_init(newsk);
> bh_lock_sock(newsk);
CC Eric Biederman
It looks this should be submitted for 'net' tree, not 'net-next'
Fixes: 26abe14379f8 ("net: Modify sk_alloc to not reference count the netns of
kernel sockets.")
Acked-by: Eric Dumazet <[email protected]>
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