From a898def29e4119bc01ebe7ca97423181f4c0ea2d Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 22 Feb 2010 17:04:49 -0800 Subject: 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 Acked-by: David S. Miller Signed-off-by: Paul E. McKenney 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 --- net/core/dev.c | 2 +- net/core/filter.c | 6 +++--- net/core/rtnetlink.c | 8 ++++++++ net/core/sock.c | 3 ++- 4 files changed, 14 insertions(+), 5 deletions(-) (limited to 'net/core') diff --git a/net/core/dev.c b/net/core/dev.c index ec874218b20..bb1f1da2b8a 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -2041,7 +2041,7 @@ gso: 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 08db7b9143a..3541aa48d21 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -86,7 +86,7 @@ int sk_filter(struct sock *sk, struct sk_buff *skb) 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 @@ int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk) } 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 @@ int sk_detach_filter(struct sock *sk) 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 794bcb897ff..4c7d3f635ba 100644 --- a/net/core/rtnetlink.c +++ b/net/core/rtnetlink.c @@ -89,6 +89,14 @@ int rtnl_is_locked(void) } 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 e1f6f225f01..305cba401ae 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1073,7 +1073,8 @@ static void __sk_free(struct sock *sk) 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); -- cgit v1.2.3-70-g09d2