[PATCH net] tun: add a missing rcu_read_unlock() in error path

[Eric Dumazet]

In my latest patch I missed one rcu_read_unlock(), in case
device is down.

Fixes: 4477138fa0ae ("tun: properly test for IFF_UP")
Signed-off-by: Eric Dumazet <eduma...@google.com>
Reported-by: syzbot <syzkal...@googlegroups.com>
---
 drivers/net/tun.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 
0d343359f647ff58fee35462358827e61857c837..e9ca1c088d0b11611e4d80268ced3806db05cffb
 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1960,6 +1960,7 @@ static ssize_t tun_get_user(struct tun_struct *tun, 
struct tun_file *tfile,
        rcu_read_lock();
        if (unlikely(!(tun->dev->flags & IFF_UP))) {
                err = -EIO;
+               rcu_read_unlock();
                goto drop;
        }
 
-- 
2.21.0.225.g810b269d1ac-goog