Merge branch 'sctp-race-fix'
Xin Long says:
====================
sctp: fix the race condition in sctp_destroy_sock in a proper way
The original fix introduced a dead lock, and has to be removed in
Patch 1/2, and we will get a proper way to fix it in Patch 2/2.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index b7b9013..40f9f6c 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -357,6 +357,18 @@
return af;
}
+static void sctp_auto_asconf_init(struct sctp_sock *sp)
+{
+ struct net *net = sock_net(&sp->inet.sk);
+
+ if (net->sctp.default_auto_asconf) {
+ spin_lock(&net->sctp.addr_wq_lock);
+ list_add_tail(&sp->auto_asconf_list, &net->sctp.auto_asconf_splist);
+ spin_unlock(&net->sctp.addr_wq_lock);
+ sp->do_auto_asconf = 1;
+ }
+}
+
/* Bind a local address either to an endpoint or to an association. */
static int sctp_do_bind(struct sock *sk, union sctp_addr *addr, int len)
{
@@ -418,8 +430,10 @@
return -EADDRINUSE;
/* Refresh ephemeral port. */
- if (!bp->port)
+ if (!bp->port) {
bp->port = inet_sk(sk)->inet_num;
+ sctp_auto_asconf_init(sp);
+ }
/* Add the address to the bind address list.
* Use GFP_ATOMIC since BHs will be disabled.
@@ -1520,9 +1534,11 @@
/* Supposedly, no process has access to the socket, but
* the net layers still may.
+ * Also, sctp_destroy_sock() needs to be called with addr_wq_lock
+ * held and that should be grabbed before socket lock.
*/
- local_bh_disable();
- bh_lock_sock(sk);
+ spin_lock_bh(&net->sctp.addr_wq_lock);
+ bh_lock_sock_nested(sk);
/* Hold the sock, since sk_common_release() will put sock_put()
* and we have just a little more cleanup.
@@ -1531,7 +1547,7 @@
sk_common_release(sk);
bh_unlock_sock(sk);
- local_bh_enable();
+ spin_unlock_bh(&net->sctp.addr_wq_lock);
sock_put(sk);
@@ -4991,16 +5007,6 @@
sk_sockets_allocated_inc(sk);
sock_prot_inuse_add(net, sk->sk_prot, 1);
- if (net->sctp.default_auto_asconf) {
- spin_lock(&sock_net(sk)->sctp.addr_wq_lock);
- list_add_tail(&sp->auto_asconf_list,
- &net->sctp.auto_asconf_splist);
- sp->do_auto_asconf = 1;
- spin_unlock(&sock_net(sk)->sctp.addr_wq_lock);
- } else {
- sp->do_auto_asconf = 0;
- }
-
local_bh_enable();
return 0;
@@ -5025,9 +5031,7 @@
if (sp->do_auto_asconf) {
sp->do_auto_asconf = 0;
- spin_lock_bh(&sock_net(sk)->sctp.addr_wq_lock);
list_del(&sp->auto_asconf_list);
- spin_unlock_bh(&sock_net(sk)->sctp.addr_wq_lock);
}
sctp_endpoint_free(sp->ep);
local_bh_disable();
@@ -9398,6 +9402,8 @@
return err;
}
+ sctp_auto_asconf_init(newsp);
+
/* Move any messages in the old socket's receive queue that are for the
* peeled off association to the new socket's receive queue.
*/
