4.14-stable review patch. If anyone has any objections, please let me know.
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From: Xin Long lucien.xin@gmail.com
[ Upstream commit 654d573845f35017dc397840fa03610fef3d08b0 ]
rcu_read_lock in tun_build_skb is used to rcu_dereference tun->xdp_prog safely, rcu_read_unlock should be done in every return path.
Now I could see one place missing it, where it returns NULL in switch-case XDP_REDIRECT, another palce using rcu_read_lock wrongly, where it returns NULL in if (xdp_xmit) chunk.
So fix both in this patch.
Fixes: 761876c857cb ("tap: XDP support") Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/tun.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/drivers/net/tun.c +++ b/drivers/net/tun.c @@ -1326,6 +1326,7 @@ static struct sk_buff *tun_build_skb(str err = xdp_do_redirect(tun->dev, &xdp, xdp_prog); if (err) goto err_redirect; + rcu_read_unlock(); return NULL; case XDP_TX: xdp_xmit = true; @@ -1358,7 +1359,7 @@ static struct sk_buff *tun_build_skb(str if (xdp_xmit) { skb->dev = tun->dev; generic_xdp_tx(skb, xdp_prog); - rcu_read_lock(); + rcu_read_unlock(); return NULL; }