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authorHerbert Xu <herbert@gondor.apana.org.au>2017-02-11 19:26:46 +0800
committerDavid S. Miller <davem@davemloft.net>2017-02-17 12:28:35 -0500
commit40f9f439706073b4b0a654b3b99e18296b7990b3 (patch)
treebaa437731befae16bef34595d72e2b64c2e4a97b /net/tipc
parent98687f426bb3e93b9dbbfb614ba331192beae482 (diff)
downloadlinux-40f9f439706073b4b0a654b3b99e18296b7990b3.tar.bz2
tipc: Fix tipc_sk_reinit race conditions
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 <herbert@gondor.apana.org.au> Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc')
-rw-r--r--net/tipc/net.c4
-rw-r--r--net/tipc/socket.c30
2 files changed, 23 insertions, 11 deletions
diff --git a/net/tipc/net.c b/net/tipc/net.c
index 28bf4feeb81c..ab8a2d5d1e32 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 103d1fd058c0..6b09a778cc71 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -430,8 +430,6 @@ static int tipc_sk_create(struct net *net, struct socket *sock,
INIT_LIST_HEAD(&tsk->cong_links);
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;
@@ -441,6 +439,13 @@ 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;
@@ -2234,24 +2239,27 @@ 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)