On 02/07/2017 08:39 PM, Herbert Xu wrote:
> There are two problems with the function tipc_sk_reinit. Firstly
> it's doing a manual walk over an rhashtable. This is broken as
> an rhashtable can be resized and if you manually walk over it
> during a resize then you may miss entries.
>
> Secondly it's missing memory barriers as previously the code used
> spinlocks which provide the barriers implicitly.
>
> This patch fixes both problems.
>
> Fixes: 07f6c4bc048a ("tipc: convert tipc reference table to...")
> Signed-off-by: Herbert Xu <herb...@gondor.apana.org.au>
Acked-by: Ying Xue <ying....@windriver.com>
> ---
>
> net/tipc/net.c | 4 ++++
> net/tipc/socket.c | 30 +++++++++++++++++++-----------
> 2 files changed, 23 insertions(+), 11 deletions(-)
>
> diff --git a/net/tipc/net.c b/net/tipc/net.c
> index 28bf4fe..ab8a2d5 100644
> --- a/net/tipc/net.c
> +++ b/net/tipc/net.c
> @@ -110,6 +110,10 @@ int tipc_net_start(struct net *net, u32 addr)
> char addr_string[16];
>
> tn->own_addr = addr;
> +
> + /* Ensure that the new address is visible before we reinit. */
> + smp_mb();
> +
> tipc_named_reinit(net);
> tipc_sk_reinit(net);
>
> diff --git a/net/tipc/socket.c b/net/tipc/socket.c
> index 333c5da..20240e1 100644
> --- a/net/tipc/socket.c
> +++ b/net/tipc/socket.c
> @@ -384,8 +384,6 @@ static int tipc_sk_create(struct net *net, struct socket
> *sock,
> INIT_LIST_HEAD(&tsk->publications);
> msg = &tsk->phdr;
> tn = net_generic(sock_net(sk), tipc_net_id);
> - tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
> - NAMED_H_SIZE, 0);
>
> /* Finish initializing socket data structures */
> sock->ops = ops;
> @@ -395,6 +393,13 @@ static int tipc_sk_create(struct net *net, struct socket
> *sock,
> pr_warn("Socket create failed; port number exhausted\n");
> return -EINVAL;
> }
> +
> + /* Ensure tsk is visible before we read own_addr. */
> + smp_mb();
> +
> + tipc_msg_init(tn->own_addr, msg, TIPC_LOW_IMPORTANCE, TIPC_NAMED_MSG,
> + NAMED_H_SIZE, 0);
> +
> msg_set_origport(msg, tsk->portid);
> setup_timer(&sk->sk_timer, tipc_sk_timeout, (unsigned long)tsk);
> sk->sk_shutdown = 0;
> @@ -2267,24 +2272,27 @@ static int tipc_sk_withdraw(struct tipc_sock *tsk,
> uint scope,
> void tipc_sk_reinit(struct net *net)
> {
> struct tipc_net *tn = net_generic(net, tipc_net_id);
> - const struct bucket_table *tbl;
> - struct rhash_head *pos;
> + struct rhashtable_iter iter;
> struct tipc_sock *tsk;
> struct tipc_msg *msg;
> - int i;
>
> - rcu_read_lock();
> - tbl = rht_dereference_rcu((&tn->sk_rht)->tbl, &tn->sk_rht);
> - for (i = 0; i < tbl->size; i++) {
> - rht_for_each_entry_rcu(tsk, pos, tbl, i, node) {
> + rhashtable_walk_enter(&tn->sk_rht, &iter);
> +
> + do {
> + tsk = ERR_PTR(rhashtable_walk_start(&iter));
> + if (tsk)
> + continue;
> +
> + while ((tsk = rhashtable_walk_next(&iter)) && !IS_ERR(tsk)) {
> spin_lock_bh(&tsk->sk.sk_lock.slock);
> msg = &tsk->phdr;
> msg_set_prevnode(msg, tn->own_addr);
> msg_set_orignode(msg, tn->own_addr);
> spin_unlock_bh(&tsk->sk.sk_lock.slock);
> }
> - }
> - rcu_read_unlock();
> +
> + rhashtable_walk_stop(&iter);
> + } while (tsk == ERR_PTR(-EAGAIN));
> }
>
> static struct tipc_sock *tipc_sk_lookup(struct net *net, u32 portid)
>
