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vxlan: Don't call gro_cells_destroy() before device is unregistered

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[ 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 <mousuanming@huawei.com>
Suggested-by: Eric Dumazet <eric.dumazet@gmail.com>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Zhiqiang Liu <liuzhiqiang26@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Zhiqiang Liu 2019-03-16 17:02:54 +08:00 committed by Greg Kroah-Hartman
parent 6c362ffe2a
commit c5874f35b8
1 changed files with 1 additions and 3 deletions
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4
drivers/net/vxlan.c
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@ -3276,10 +3276,8 @@ 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);