commit eaefd1105bc431ef329599e307a07f2a36ae7872
author Eric Dumazet <eric.dumazet@gmail.com> Fri Feb 18 03:26:36 2011 +0000
committer David S. Miller <davem@davemloft.net> Tue Feb 22 10:19:31 2011 -0800
tree 658eeed417654c8f6015d4d5f957f5a1b5e9521f
parent 04cfa852ff8dab923640500ee850d19e75bacabc

net: add __rcu annotations to sk_wq and wq

Add proper RCU annotations/verbs to sk_wq and wq members

Fix __sctp_write_space() sk_sleep() abuse (and sock->wq access)

Fix sunrpc sk_sleep() abuse too

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/socket.c

diff --git a/net/socket.c b/net/socket.c
index ac2219f..9fa1e3b 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -240,17 +240,19 @@
 static struct inode *sock_alloc_inode(struct super_block *sb)
 {
 	struct socket_alloc *ei;
+	struct socket_wq *wq;
 
 	ei = kmem_cache_alloc(sock_inode_cachep, GFP_KERNEL);
 	if (!ei)
 		return NULL;
-	ei->socket.wq = kmalloc(sizeof(struct socket_wq), GFP_KERNEL);
-	if (!ei->socket.wq) {
+	wq = kmalloc(sizeof(*wq), GFP_KERNEL);
+	if (!wq) {
 		kmem_cache_free(sock_inode_cachep, ei);
 		return NULL;
 	}
-	init_waitqueue_head(&ei->socket.wq->wait);
-	ei->socket.wq->fasync_list = NULL;
+	init_waitqueue_head(&wq->wait);
+	wq->fasync_list = NULL;
+	RCU_INIT_POINTER(ei->socket.wq, wq);
 
 	ei->socket.state = SS_UNCONNECTED;
 	ei->socket.flags = 0;
@@ -273,9 +275,11 @@
 static void sock_destroy_inode(struct inode *inode)
 {
 	struct socket_alloc *ei;
+	struct socket_wq *wq;
 
 	ei = container_of(inode, struct socket_alloc, vfs_inode);
-	call_rcu(&ei->socket.wq->rcu, wq_free_rcu);
+	wq = rcu_dereference_protected(ei->socket.wq, 1);
+	call_rcu(&wq->rcu, wq_free_rcu);
 	kmem_cache_free(sock_inode_cachep, ei);
 }
 
@@ -524,7 +528,7 @@
 		module_put(owner);
 	}
 
-	if (sock->wq->fasync_list)
+	if (rcu_dereference_protected(sock->wq, 1)->fasync_list)
 		printk(KERN_ERR "sock_release: fasync list not empty!\n");
 
 	percpu_sub(sockets_in_use, 1);
@@ -1108,15 +1112,16 @@
 {
 	struct socket *sock = filp->private_data;
 	struct sock *sk = sock->sk;
+	struct socket_wq *wq;
 
 	if (sk == NULL)
 		return -EINVAL;
 
 	lock_sock(sk);
+	wq = rcu_dereference_protected(sock->wq, sock_owned_by_user(sk));
+	fasync_helper(fd, filp, on, &wq->fasync_list);
 
-	fasync_helper(fd, filp, on, &sock->wq->fasync_list);
-
-	if (!sock->wq->fasync_list)
+	if (!wq->fasync_list)
 		sock_reset_flag(sk, SOCK_FASYNC);
 	else
 		sock_set_flag(sk, SOCK_FASYNC);