From 3bf74b1aecdce719f1445200d5db7dfee2297bba Mon Sep 17 00:00:00 2001 From: stephen hemminger Date: Mon, 17 Jun 2013 12:09:57 -0700 Subject: [PATCH] vxlan: fix race between flush and incoming learning It is possible for a packet to arrive during vxlan_stop(), and have a dynamic entry created. Close this by checking if device is up. CPU1 CPU2 vxlan_stop vxlan_flush hash_lock acquired vxlan_encap_recv vxlan_snoop waiting for hash_lock hash_lock relased vxlan_flush done hash_lock acquired vxlan_fdb_create This is a day-one bug in vxlan goes back to 3.7. Signed-off-by: Stephen Hemminger Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 3b1d2ee7156b..577a069a6dde 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -571,7 +571,6 @@ static void vxlan_snoop(struct net_device *dev, { struct vxlan_dev *vxlan = netdev_priv(dev); struct vxlan_fdb *f; - int err; f = vxlan_find_mac(vxlan, src_mac); if (likely(f)) { @@ -588,12 +587,15 @@ static void vxlan_snoop(struct net_device *dev, } else { /* learned new entry */ spin_lock(&vxlan->hash_lock); - err = vxlan_fdb_create(vxlan, src_mac, src_ip, - NUD_REACHABLE, - NLM_F_EXCL|NLM_F_CREATE, - vxlan->dst_port, - vxlan->default_dst.remote_vni, - 0, NTF_SELF); + + /* close off race between vxlan_flush and incoming packets */ + if (netif_running(dev)) + vxlan_fdb_create(vxlan, src_mac, src_ip, + NUD_REACHABLE, + NLM_F_EXCL|NLM_F_CREATE, + vxlan->dst_port, + vxlan->default_dst.remote_vni, + 0, NTF_SELF); spin_unlock(&vxlan->hash_lock); } } -- 2.39.5