Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757587Ab0BLACx (ORCPT ); Thu, 11 Feb 2010 19:02:53 -0500 Received: from e2.ny.us.ibm.com ([32.97.182.142]:44611 "EHLO e2.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757524Ab0BLABJ (ORCPT ); Thu, 11 Feb 2010 19:01:09 -0500 From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: mingo@elte.hu, laijs@cn.fujitsu.com, dipankar@in.ibm.com, akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca, josh@joshtriplett.org, dvhltc@us.ibm.com, niv@us.ibm.com, tglx@linutronix.de, peterz@infradead.org, rostedt@goodmis.org, Valdis.Kletnieks@vt.edu, dhowells@redhat.com, "Paul E. McKenney" Subject: [PATCH tip/core/rcu 05/13] net: add checking to rcu_dereference() primitives Date: Thu, 11 Feb 2010 16:00:31 -0800 Message-Id: <1265932839-25899-5-git-send-email-paulmck@linux.vnet.ibm.com> X-Mailer: git-send-email 1.6.6 In-Reply-To: <20100212000016.GA25781@linux.vnet.ibm.com> References: <20100212000016.GA25781@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8854 Lines: 248 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. Signed-off-by: Paul E. McKenney --- include/linux/rtnetlink.h | 3 +++ include/net/addrconf.h | 4 +++- net/core/dev.c | 2 +- net/core/filter.c | 6 +++--- net/core/rtnetlink.c | 8 ++++++++ net/core/sock.c | 3 ++- net/decnet/dn_route.c | 14 +++++++------- net/ipv4/route.c | 14 +++++++------- net/packet/af_packet.c | 2 +- 9 files changed, 35 insertions(+), 21 deletions(-) diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h index 05330fc..5c52fa4 100644 --- a/include/linux/rtnetlink.h +++ b/include/linux/rtnetlink.h @@ -735,6 +735,9 @@ extern void rtnl_lock(void); extern void rtnl_unlock(void); extern int rtnl_trylock(void); extern int rtnl_is_locked(void); +#ifdef CONFIG_PROVE_LOCKING +extern int lockdep_rtnl_is_held(void); +#endif /* #ifdef CONFIG_PROVE_LOCKING */ extern void rtnetlink_init(void); extern void __rtnl_unlock(void); diff --git a/include/net/addrconf.h b/include/net/addrconf.h index 0f7c378..45375b4 100644 --- a/include/net/addrconf.h +++ b/include/net/addrconf.h @@ -177,7 +177,9 @@ extern int unregister_inet6addr_notifier(struct notifier_block *nb); static inline struct inet6_dev * __in6_dev_get(struct net_device *dev) { - return rcu_dereference(dev->ip6_ptr); + return rcu_dereference_check(dev->ip6_ptr, + rcu_read_lock_held() || + lockdep_rtnl_is_held()); } static inline struct inet6_dev * diff --git a/net/core/dev.c b/net/core/dev.c index be9924f..0d0ff82 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 08db7b9..3541aa4 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 794bcb8..4c7d3f6 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 e1f6f22..305cba4 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); diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c index a032840..a7bf03c 100644 --- a/net/decnet/dn_route.c +++ b/net/decnet/dn_route.c @@ -1155,8 +1155,8 @@ static int __dn_route_output_key(struct dst_entry **pprt, const struct flowi *fl if (!(flags & MSG_TRYHARD)) { rcu_read_lock_bh(); - for(rt = rcu_dereference(dn_rt_hash_table[hash].chain); rt; - rt = rcu_dereference(rt->u.dst.dn_next)) { + for (rt = rcu_dereference_bh(dn_rt_hash_table[hash].chain); rt; + rt = rcu_dereference_bh(rt->u.dst.dn_next)) { if ((flp->fld_dst == rt->fl.fld_dst) && (flp->fld_src == rt->fl.fld_src) && (flp->mark == rt->fl.mark) && @@ -1618,9 +1618,9 @@ int dn_cache_dump(struct sk_buff *skb, struct netlink_callback *cb) if (h > s_h) s_idx = 0; rcu_read_lock_bh(); - for(rt = rcu_dereference(dn_rt_hash_table[h].chain), idx = 0; + for(rt = rcu_dereference_bh(dn_rt_hash_table[h].chain), idx = 0; rt; - rt = rcu_dereference(rt->u.dst.dn_next), idx++) { + rt = rcu_dereference_bh(rt->u.dst.dn_next), idx++) { if (idx < s_idx) continue; skb_dst_set(skb, dst_clone(&rt->u.dst)); @@ -1654,12 +1654,12 @@ static struct dn_route *dn_rt_cache_get_first(struct seq_file *seq) for(s->bucket = dn_rt_hash_mask; s->bucket >= 0; --s->bucket) { rcu_read_lock_bh(); - rt = dn_rt_hash_table[s->bucket].chain; + rt = rcu_dereference_bh(dn_rt_hash_table[s->bucket].chain); if (rt) break; rcu_read_unlock_bh(); } - return rcu_dereference(rt); + return rt; } static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_route *rt) @@ -1674,7 +1674,7 @@ static struct dn_route *dn_rt_cache_get_next(struct seq_file *seq, struct dn_rou rcu_read_lock_bh(); rt = dn_rt_hash_table[s->bucket].chain; } - return rcu_dereference(rt); + return rcu_dereference_bh(rt); } static void *dn_rt_cache_seq_start(struct seq_file *seq, loff_t *pos) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index e446496..3476b3b 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -287,12 +287,12 @@ static struct rtable *rt_cache_get_first(struct seq_file *seq) if (!rt_hash_table[st->bucket].chain) continue; rcu_read_lock_bh(); - r = rcu_dereference(rt_hash_table[st->bucket].chain); + r = rcu_dereference_bh(rt_hash_table[st->bucket].chain); while (r) { if (dev_net(r->u.dst.dev) == seq_file_net(seq) && r->rt_genid == st->genid) return r; - r = rcu_dereference(r->u.dst.rt_next); + r = rcu_dereference_bh(r->u.dst.rt_next); } rcu_read_unlock_bh(); } @@ -314,7 +314,7 @@ static struct rtable *__rt_cache_get_next(struct seq_file *seq, rcu_read_lock_bh(); r = rt_hash_table[st->bucket].chain; } - return rcu_dereference(r); + return rcu_dereference_bh(r); } static struct rtable *rt_cache_get_next(struct seq_file *seq, @@ -2687,8 +2687,8 @@ int __ip_route_output_key(struct net *net, struct rtable **rp, hash = rt_hash(flp->fl4_dst, flp->fl4_src, flp->oif, rt_genid(net)); rcu_read_lock_bh(); - for (rth = rcu_dereference(rt_hash_table[hash].chain); rth; - rth = rcu_dereference(rth->u.dst.rt_next)) { + for (rth = rcu_dereference_bh(rt_hash_table[hash].chain); rth; + rth = rcu_dereference_bh(rth->u.dst.rt_next)) { if (rth->fl.fl4_dst == flp->fl4_dst && rth->fl.fl4_src == flp->fl4_src && rth->fl.iif == 0 && @@ -3006,8 +3006,8 @@ int ip_rt_dump(struct sk_buff *skb, struct netlink_callback *cb) if (!rt_hash_table[h].chain) continue; rcu_read_lock_bh(); - for (rt = rcu_dereference(rt_hash_table[h].chain), idx = 0; rt; - rt = rcu_dereference(rt->u.dst.rt_next), idx++) { + for (rt = rcu_dereference_bh(rt_hash_table[h].chain), idx = 0; rt; + rt = rcu_dereference_bh(rt->u.dst.rt_next), idx++) { if (!net_eq(dev_net(rt->u.dst.dev), net) || idx < s_idx) continue; if (rt_is_expired(rt)) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index f126d18..939471e 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -508,7 +508,7 @@ static inline unsigned int run_filter(struct sk_buff *skb, 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 != NULL) res = sk_run_filter(skb, filter->insns, filter->len); rcu_read_unlock_bh(); -- 1.6.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/