Re: lockdep warning

From: Jiri Kosina
Date: Fri Feb 22 2008 - 08:20:54 EST


On Fri, 22 Feb 2008, Anders Eriksson wrote:

> > This needs to be CCed to netdev.
> > Any chance that
> > git revert 69cc64d8d92
> > makes this report go away?
> I'll have to install a git repo to check, or maybe you can send me the diff to
> reverse vs. 2.6.25-rc2?

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 7bb6a9a..a16cf1e 100644
--- 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 c663fa5..8e17f65 100644
--- 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)
--
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