On Mon, Jul 27, 2015 at 7:21 AM, Sowmini Varadhan <sowmini.varad...@oracle.com> wrote: > > I'm running into a netns refcnt issue, and I suspect that > eeb1bd5c has something to do with it (perhaps we need an > additional change in sk_clone_lock() after eeb1bd5c). > Here's the problem: > > When we create an syn_recv sock based on a kernel listen sock, we > take a get_net() ref with a stack similar to the one shown below. > Note that the parent (kernel, listen) sock itself has not taken > a get_net() ref, because it explicitly calls sock_create_kern(). > > get_net /* for the newsk */ > sk_clone_lock > inet_csk_clone_lock > tcp_create_openreq_child > tcp_v4_syn_recv_sock > tcp_check_req > tcp_v4_do_rcv > tcp_v4_rcv > : > > But it's not clear to me where this refcnt will be released: > in my case, I expect to create/cleanup kernel sockets as part > of ->init/->exit for my module, but because the accept socket > has a netns refcnt, it blocks cleanup_net(), thus my ->exit > pernet_subsys op cannot run and clean this up, and we have a leak.
That refcnt should be released in sock destructor too, when the tcp connection is terminated. > > I think that sk_clone_lock() should only do a get_net() if the parent > is not a kernel socket (making this similar to sk_alloc()), i.e., > Given the fact that sk_destruct() checks for sk_net_refcnt, your patch makes sense to me. But I am not sure how a TCP kernel socket is supposed to use. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
