net: Add checking to rcu_dereference() primitives
Update rcu_dereference() primitives to use new lockdep-based
checking. The rcu_dereference() in __in6_dev_get() may be
protected either by rcu_read_lock() or RTNL, per Eric Dumazet.
The rcu_dereference() in __sk_free() is protected by the fact
that it is never reached if an update could change it. Check
for this by using rcu_dereference_check() to verify that the
struct sock's ->sk_wmem_alloc counter is zero.
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1266887105-1528-5-git-send-email-paulmck@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/net/core/dev.c b/net/core/dev.c
index ec87421..bb1f1da 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2041,7 +2041,7 @@
rcu_read_lock_bh();
txq = dev_pick_tx(dev, skb);
- q = rcu_dereference(txq->qdisc);
+ q = rcu_dereference_bh(txq->qdisc);
#ifdef CONFIG_NET_CLS_ACT
skb->tc_verd = SET_TC_AT(skb->tc_verd, AT_EGRESS);
diff --git a/net/core/filter.c b/net/core/filter.c
index 08db7b9..3541aa4 100644
--- a/net/core/filter.c
+++ b/net/core/filter.c
@@ -86,7 +86,7 @@
return err;
rcu_read_lock_bh();
- filter = rcu_dereference(sk->sk_filter);
+ filter = rcu_dereference_bh(sk->sk_filter);
if (filter) {
unsigned int pkt_len = sk_run_filter(skb, filter->insns,
filter->len);
@@ -521,7 +521,7 @@
}
rcu_read_lock_bh();
- old_fp = rcu_dereference(sk->sk_filter);
+ old_fp = rcu_dereference_bh(sk->sk_filter);
rcu_assign_pointer(sk->sk_filter, fp);
rcu_read_unlock_bh();
@@ -536,7 +536,7 @@
struct sk_filter *filter;
rcu_read_lock_bh();
- filter = rcu_dereference(sk->sk_filter);
+ filter = rcu_dereference_bh(sk->sk_filter);
if (filter) {
rcu_assign_pointer(sk->sk_filter, NULL);
sk_filter_delayed_uncharge(sk, filter);
diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 794bcb8..4c7d3f6 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -89,6 +89,14 @@
}
EXPORT_SYMBOL(rtnl_is_locked);
+#ifdef CONFIG_PROVE_LOCKING
+int lockdep_rtnl_is_held(void)
+{
+ return lockdep_is_held(&rtnl_mutex);
+}
+EXPORT_SYMBOL(lockdep_rtnl_is_held);
+#endif /* #ifdef CONFIG_PROVE_LOCKING */
+
static struct rtnl_link *rtnl_msg_handlers[NPROTO];
static inline int rtm_msgindex(int msgtype)
diff --git a/net/core/sock.c b/net/core/sock.c
index e1f6f22..305cba4 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -1073,7 +1073,8 @@
if (sk->sk_destruct)
sk->sk_destruct(sk);
- filter = rcu_dereference(sk->sk_filter);
+ filter = rcu_dereference_check(sk->sk_filter,
+ atomic_read(&sk->sk_wmem_alloc) == 0);
if (filter) {
sk_filter_uncharge(sk, filter);
rcu_assign_pointer(sk->sk_filter, NULL);