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It drops only packets from > it does 2 things - adds a namespace check and a performance based change > with the way the list is walked. I believe no. All items are removed before the patch and all items are walked after the patch, similar O(n) operation. >> the same namespace in the pneigh_queue_purge() where network interface >> state change is detected. This is enough to prevent the problem for the >> whole node preserving original semantics of the code. >> > >> diff --git a/net/core/neighbour.c b/net/core/neighbour.c >> index 54625287ee5b..213ec0be800b 100644 >> --- a/net/core/neighbour.c >> +++ b/net/core/neighbour.c >> @@ -386,8 +396,7 @@ static int __neigh_ifdown(struct neigh_table *tbl, struct net_device *dev, >> neigh_flush_dev(tbl, dev, skip_perm); >> pneigh_ifdown_and_unlock(tbl, dev); >> >> - del_timer_sync(&tbl->proxy_timer); > why are you removing this line too? Because we have packets in the queue after the purge and they have to be processed. May be we should better do if (skb_queue_empty(&tbl->proxy_queue))    del_timer_sync(&tbl->proxy_timer); after the purge. That could be more correct. >> - pneigh_queue_purge(&tbl->proxy_queue); >> + pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev)); >> return 0; >> } >>