From: Zhiqiang Liu Date: Sat, 16 Mar 2019 09:02:54 +0000 (+0800) Subject: vxlan: Don't call gro_cells_destroy() before device is unregistered X-Git-Tag: v4.14.110~90 X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=bf583844131acbaea3e0436e47bca1214c384029;p=users%2Fjedix%2Flinux-maple.git vxlan: Don't call gro_cells_destroy() before device is unregistered [ Upstream commit cc4807bb609230d8959fd732b0bf3bd4c2de8eac ] Commit ad6c9986bcb62 ("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: 58ce31cca1ff ("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 Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/net/vxlan.c b/drivers/net/vxlan.c index df48f65c4f90..2fbaa279988e 100644 --- a/drivers/net/vxlan.c +++ b/drivers/net/vxlan.c @@ -3793,10 +3793,8 @@ static void __net_exit vxlan_exit_net(struct net *net) /* 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, &list); - } } unregister_netdevice_many(&list);