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authorXin Long <lucien.xin@gmail.com>2017-11-19 19:31:04 +0800
committerDavid S. Miller <davem@davemloft.net>2017-11-19 21:22:31 +0900
commit654d573845f35017dc397840fa03610fef3d08b0 (patch)
treeca78d6425d2624b845c0b57b34e1f740a5fda841 /drivers/net/tun.c
parented66dfaf236c04d414de1d218441296e57fb2bd2 (diff)
downloadlinux-654d573845f35017dc397840fa03610fef3d08b0.tar.bz2
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: 761876c857cb ("tap: XDP support") Signed-off-by: Xin Long <lucien.xin@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/tun.c')
-rw-r--r--drivers/net/tun.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 6bb1e604aadd..5a2ea78a008f 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -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;
}