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>

1 files changed, 7 insertions, 7 deletions

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index d62b05d33384..4f11faa5c824 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,
@@ -2689,8 +2689,8 @@ 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 &&
@@ -3008,8 +3008,8 @@ 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))