On Tue, Sep 19, 2017 at 3:21 AM, Nixiaoming <nixiaom...@huawei.com> wrote: > On Fri, Sep 15, 2017 at 10:46 AM, Willem de Bruijn > > <willemdebruijn.ker...@gmail.com> wrote: > >> > >> In case of failure we also need to unlink and free match. I > >> sent the following: > >> > >> http://patchwork.ozlabs.org/patch/813945/ > > > > + spin_lock(&po->bind_lock); > > + if (po->running && > > + match->type == type && > > match->prot_hook.type == po->prot_hook.type && > > match->prot_hook.dev == po->prot_hook.dev) { > > err = -ENOSPC; > > @@ -1761,6 +1760,13 @@ static int fanout_add(struct sock *sk, u16 id, u16 > type_flags) > > err = 0; > > } > > } > > + spin_unlock(&po->bind_lock); > > + > > + if (err && !refcount_read(&match->sk_ref)) { > > + list_del(&match->list); > > + kfree(match); > > + } > > > > > > In the function fanout_add add spin_lock to protect po-> running and po-> > fanout, > > then whether it should be in the function fanout_release also add spin_lock > protection ?
po->bind_lock is held when registering and unregistering the protocol hook. fanout_release does access po->running or prot_hook. It is called from packet_release, which does hold the bind_lock when unregistering the protocol hook.
