[NEIGH]: Add debugging check when adding timers.

If we double-add a neighbour entry timer, which should be
impossible but has been reported, dump the current state of
the entry so that we can debug this.

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

1 files changed, 14 insertions, 9 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 5f160082aafc..4128fc76ac3a 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -727,6 +727,13 @@ static __inline__ int neigh_max_probes(struct neighbour *n)
                 p->ucast_probes + p->app_probes + p->mcast_probes);
 }
 
+static inline void neigh_add_timer(struct neighbour *n, unsigned long when)
+{
+        if (unlikely(mod_timer(&n->timer, when))) {
+                printk("NEIGH: BUG, double timer add, state is %x\n",
+                       n->nud_state);
+        }
+}
 
 /* Called when a timer expires for a neighbour entry. */
 
@@ -811,8 +818,7 @@ static void neigh_timer_handler(unsigned long arg)
                 neigh_hold(neigh);
                 if (time_before(next, jiffies + HZ/2))
                         next = jiffies + HZ/2;
-                neigh->timer.expires = next;
-                add_timer(&neigh->timer);
+                neigh_add_timer(neigh, next);
         }
         if (neigh->nud_state & (NUD_INCOMPLETE | NUD_PROBE)) {
                 struct sk_buff *skb = skb_peek(&neigh->arp_queue);
@@ -854,8 +860,7 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
                         atomic_set(&neigh->probes, neigh->parms->ucast_probes);
                         neigh->nud_state     = NUD_INCOMPLETE;
                         neigh_hold(neigh);
-                        neigh->timer.expires = now + 1;
-                        add_timer(&neigh->timer);
+                        neigh_add_timer(neigh, now + 1);
                 } else {
                         neigh->nud_state = NUD_FAILED;
                         write_unlock_bh(&neigh->lock);
@@ -868,8 +873,8 @@ int __neigh_event_send(struct neighbour *neigh, struct sk_buff *skb)
                 NEIGH_PRINTK2("neigh %p is delayed.\n", neigh);
                 neigh_hold(neigh);
                 neigh->nud_state = NUD_DELAY;
-                neigh->timer.expires = jiffies + neigh->parms->delay_probe_time;
-                add_timer(&neigh->timer);
+                neigh_add_timer(neigh,
+                                jiffies + neigh->parms->delay_probe_time);
         }
 
         if (neigh->nud_state == NUD_INCOMPLETE) {
@@ -1015,10 +1020,10 @@ int neigh_update(struct neighbour *neigh, const u8 *lladdr, u8 new,
                 neigh_del_timer(neigh);
                 if (new & NUD_IN_TIMER) {
                         neigh_hold(neigh);
-                        neigh->timer.expires = jiffies + 
+                        neigh_add_timer(neigh, (jiffies + 
                                                 ((new & NUD_REACHABLE) ? 
-                                                 neigh->parms->reachable_time : 0);
-                        add_timer(&neigh->timer);
+                                                 neigh->parms->reachable_time :
+                                                 0)));
                 }
                 neigh->nud_state = new;
         }