Revert "[NDISC]: Fix race in generic address resolution"

This reverts commit 69cc64d8d92bf852f933e90c888dfff083bd4fc9.

It causes recursive locking in IPV6 because unlike other
neighbour layer clients, it even needs neighbour cache
entries to send neighbour soliciation messages :-(

We'll have to find another way to fix this race.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 7bb6a9a1256df6a082d0792feca42db7d18ec0f5..a16cf1ec5e5ebe9fc100cb027c740c9387184472 100644 (file)
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -834,12 +834,18 @@ static void neigh_timer_handler(unsigned long arg)
        }
        if (neigh->nud_state & (NUD_INCOMPLETE | NUD_PROBE)) {
                struct sk_buff *skb = skb_peek(&neigh->arp_queue);
-
+               /* keep skb alive even if arp_queue overflows */
+               if (skb)
+                       skb_get(skb);
+               write_unlock(&neigh->lock);
                neigh->ops->solicit(neigh, skb);
                atomic_inc(&neigh->probes);
-       }
+               if (skb)
+                       kfree_skb(skb);
+       } else {
 out:
-       write_unlock(&neigh->lock);
+               write_unlock(&neigh->lock);
+       }
 
        if (notify)
                neigh_update_notify(neigh);

diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index c663fa5339ee9cbadef76d947455806ba2db8425..8e17f65f400215a72c3ac3effb908071255d2747 100644 (file)
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -368,6 +368,7 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
                if (!(neigh->nud_state&NUD_VALID))
                        printk(KERN_DEBUG "trying to ucast probe in NUD_INVALID\n");
                dst_ha = neigh->ha;
+               read_lock_bh(&neigh->lock);
        } else if ((probes -= neigh->parms->app_probes) < 0) {
 #ifdef CONFIG_ARPD
                neigh_app_ns(neigh);
@@ -377,6 +378,8 @@ static void arp_solicit(struct neighbour *neigh, struct sk_buff *skb)
 
        arp_send(ARPOP_REQUEST, ETH_P_ARP, target, dev, saddr,
                 dst_ha, dev->dev_addr, NULL);
+       if (dst_ha)
+               read_unlock_bh(&neigh->lock);
 }
 
 static int arp_ignore(struct in_device *in_dev, __be32 sip, __be32 tip)