releases/5.0.3/vxlan-fix-gro-cells-race-condition-between-receive-and-link-delete.patch

   1 From foo@baz Thu Mar 14 23:19:55 PDT 2019
   2 From: Stefano Brivio <sbrivio@redhat.com>
   3 Date: Fri, 8 Mar 2019 16:40:57 +0100
   4 Subject: vxlan: Fix GRO cells race condition between receive and link delete
   5
   6 From: Stefano Brivio <sbrivio@redhat.com>
   7
   8 [ Upstream commit ad6c9986bcb627c7c22b8f9e9a934becc27df87c ]
   9
  10 If we receive a packet while deleting a VXLAN device, there's a chance
  11 vxlan_rcv() is called at the same time as vxlan_dellink(). This is fine,
  12 except that vxlan_dellink() should never ever touch stuff that's still in
  13 use, such as the GRO cells list.
  14
  15 Otherwise, vxlan_rcv() crashes while queueing packets via
  16 gro_cells_receive().
  17
  18 Move the gro_cells_destroy() to vxlan_uninit(), which runs after the RCU
  19 grace period is elapsed and nothing needs the gro_cells anymore.
  20
  21 This is now done in the same way as commit 8e816df87997 ("geneve: Use GRO
  22 cells infrastructure.") originally implemented for GENEVE.
  23
  24 Reported-by: Jianlin Shi <jishi@redhat.com>
  25 Fixes: 58ce31cca1ff ("vxlan: GRO support at tunnel layer")
  26 Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
  27 Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
  28 Reviewed-by: Eric Dumazet <edumazet@google.com>
  29 Signed-off-by: David S. Miller <davem@davemloft.net>
  30 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  31 ---
  32  drivers/net/vxlan.c |    3 ++-
  33  1 file changed, 2 insertions(+), 1 deletion(-)
  34
  35 --- a/drivers/net/vxlan.c
  36 +++ b/drivers/net/vxlan.c
  37 @@ -2693,6 +2693,8 @@ static void vxlan_uninit(struct net_devi
  38  {
  39         struct vxlan_dev *vxlan = netdev_priv(dev);
  40
  41 +       gro_cells_destroy(&vxlan->gro_cells);
  42 +
  43         vxlan_fdb_delete_default(vxlan, vxlan->cfg.vni);
  44
  45         free_percpu(dev->tstats);
  46 @@ -3794,7 +3796,6 @@ static void vxlan_dellink(struct net_dev
  47
  48         vxlan_flush(vxlan, true);
  49
  50 -       gro_cells_destroy(&vxlan->gro_cells);
  51         list_del(&vxlan->next);
  52         unregister_netdevice_queue(dev, head);
  53  }