From 64c6f4bbca748c3b2101469a76d88b7cd1c00476 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Wed, 1 May 2019 18:08:34 -0700 Subject: neighbor: Reset gc_entries counter if new entry is released before insert Ian and Alan both reported seeing overflows after upgrades to 5.x kernels: neighbour: arp_cache: neighbor table overflow! Alan's mpls script helped get to the bottom of this bug. When a new entry is created the gc_entries counter is bumped in neigh_alloc to check if a new one is allowed to be created. ___neigh_create then searches for an existing entry before inserting the just allocated one. If an entry already exists, the new one is dropped in favor of the existing one. In this case the cleanup path needs to drop the gc_entries counter. There is no memory leak, only a counter leak. Fixes: 58956317c8d ("neighbor: Improve garbage collection") Reported-by: Ian Kumlien Reported-by: Alan Maguire Signed-off-by: David Ahern Tested-by: Alan Maguire Signed-off-by: David S. Miller --- net/core/neighbour.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/core/neighbour.c') diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 30f6fd8f68e0..aff051e5521d 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -663,6 +663,8 @@ out: out_tbl_unlock: write_unlock_bh(&tbl->lock); out_neigh_release: + if (!exempt_from_gc) + atomic_dec(&tbl->gc_entries); neigh_release(n); goto out; } -- cgit v1.2.3-59-g8ed1b