Commit 654d5738 authored by Xin Long's avatar Xin Long Committed by David S. Miller

tun: fix rcu_read_lock imbalance in tun_build_skb

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: 761876c8 ("tap: XDP support")
Signed-off-by: default avatarXin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent ed66dfaf
......@@ -1485,6 +1485,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
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;
......@@ -1517,7 +1518,7 @@ static struct sk_buff *tun_build_skb(struct tun_struct *tun,
if (xdp_xmit) {
skb->dev = tun->dev;
generic_xdp_tx(skb, xdp_prog);
rcu_read_lock();
rcu_read_unlock();
return NULL;
}
......
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