From 2269b0f115d3a8b725b4cdd1d0e4ef0c5bb2603f Mon Sep 17 00:00:00 2001 From: Zhiqiang Liu Date: Sat, 16 Mar 2019 17:02:54 +0800 Subject: [PATCH] vxlan: Don't call gro_cells_destroy() before device is unregistered Commit 81e48eca1a654 ("vxlan: Fix GRO cells race condition between receive and link delete") fixed a race condition for the typical case a vxlan device is dismantled from the current netns. But if a netns is dismantled, vxlan_destroy_tunnels() is called to schedule a unregister_netdevice_queue() of all the vxlan tunnels that are related to this netns. In vxlan_destroy_tunnels(), gro_cells_destroy() is called and finished before unregister_netdevice_queue(). This means that the gro_cells_destroy() call is done too soon, for the same reasons explained in above commit. So we need to fully respect the RCU rules, and thus must remove the gro_cells_destroy() call or risk use after-free. Fixes: e57059e63184 ("vxlan: GRO support at tunnel layer") Signed-off-by: Suanming.Mou Suggested-by: Eric Dumazet Reviewed-by: Stefano Brivio Reviewed-by: Zhiqiang Liu Signed-off-by: David S. Miller --- drivers/net/vxlan.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index 077f1b9f27616..d76dfed8d9bbe 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -4335,10 +4335,8 @@ static void vxlan_destroy_tunnels(struct net *net, struct list_head *head) /* If vxlan->dev is in the same netns, it has already been added * to the list by the previous loop. */ - if (!net_eq(dev_net(vxlan->dev), net)) { - gro_cells_destroy(&vxlan->gro_cells); + if (!net_eq(dev_net(vxlan->dev), net)) unregister_netdevice_queue(vxlan->dev, head); - } } for (h = 0; h < PORT_HASH_SIZE; ++h) -- 2.39.5