diff options
| author | David Ahern | 2018-12-10 13:54:07 -0800 |
|---|---|---|
| committer | David S. Miller | 2018-12-10 17:41:35 -0800 |
| commit | 8cc196d6ef86bbab01dbf16f6c596cf56aa0839e (patch) | |
| tree | df782409e9117f4a333bc68cd2567ffc96070270 /net/core | |
| parent | 93698321f72cb351ae6ab59185b611ba26e6e1d0 (diff) | |
neighbor: gc_list changes should be protected by table lock
Adding and removing neighbor entries to / from the gc_list need to be
done while holding the table lock; a couple of places were missed in the
original patch.
Move the list_add_tail in neigh_alloc to ___neigh_create where the lock
is already obtained. Since neighbor entries should rarely be moved
to/from PERMANENT state, add lock/unlock around the gc_list changes in
neigh_change_state rather than extending the lock hold around all
neighbor updates.
Fixes: 58956317c8de ("neighbor: Improve garbage collection")
Reported-by: Andrei Vagin <avagin@gmail.com>
Reported-by: syzbot+6cc2fd1d3bdd2e007363@syzkaller.appspotmail.com
Reported-by: syzbot+35e87b87c00f386b041f@syzkaller.appspotmail.com
Reported-by: syzbot+b354d1fb59091ea73c37@syzkaller.appspotmail.com
Reported-by: syzbot+3ddead5619658537909b@syzkaller.appspotmail.com
Reported-by: syzbot+424d47d5c456ce8b2bbe@syzkaller.appspotmail.com
Reported-by: syzbot+e4d42eb35f6a27b0a628@syzkaller.appspotmail.com
Signed-off-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/neighbour.c | 15 |
1 files changed, 10 insertions, 5 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c index c3b58712e98b..03fdc5ae66b0 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -138,11 +138,17 @@ static void neigh_change_state(struct neighbour *n, u8 new) * add to the gc list if new state is not permanent */ if (new_is_perm && on_gc_list) { + write_lock_bh(&n->tbl->lock); list_del_init(&n->gc_list); + write_unlock_bh(&n->tbl->lock); + atomic_dec(&n->tbl->gc_entries); } else if (!new_is_perm && !on_gc_list) { /* add entries to the tail; cleaning removes from the front */ + write_lock_bh(&n->tbl->lock); list_add_tail(&n->gc_list, &n->tbl->gc_list); + write_unlock_bh(&n->tbl->lock); + atomic_inc(&n->tbl->gc_entries); } } @@ -390,11 +396,7 @@ do_alloc: n->tbl = tbl; refcount_set(&n->refcnt, 1); n->dead = 1; - - if (!permanent) - list_add_tail(&n->gc_list, &n->tbl->gc_list); - else - INIT_LIST_HEAD(&n->gc_list); + INIT_LIST_HEAD(&n->gc_list); atomic_inc(&tbl->entries); out: @@ -616,6 +618,9 @@ static struct neighbour *___neigh_create(struct neigh_table *tbl, } n->dead = 0; + if (!permanent) + list_add_tail(&n->gc_list, &n->tbl->gc_list); + if (want_ref) neigh_hold(n); rcu_assign_pointer(n->next, |