From: Eric Dumazet <edumazet@xxxxxxxxxx>
commit 6289a98f0817a4a457750d6345e754838eae9439 upstream.
After adopting CONFIG_PCPU_DEV_REFCNT=n option, syzbot was able to trigger
a warning [1]
Issue here is that:
- all dev_put() should be paired with a corresponding prior dev_hold().
- A driver doing a dev_put() in its ndo_uninit() MUST also
do a dev_hold() in its ndo_init(), only when ndo_init()
is returning 0.
Otherwise, register_netdevice() would call ndo_uninit()
in its error path and release a refcount too soon.
Fixes: 919067cc845f ("net: add CONFIG_PCPU_DEV_REFCNT")
Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reported-by: syzbot <syzkaller@xxxxxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/sit.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/net/ipv6/sit.c
+++ b/net/ipv6/sit.c
@@ -209,8 +209,6 @@ static int ipip6_tunnel_create(struct ne
ipip6_tunnel_clone_6rd(dev, sitn);
- dev_hold(dev);
-
ipip6_tunnel_link(sitn, t);
return 0;
@@ -1393,7 +1391,7 @@ static int ipip6_tunnel_init(struct net_
dev->tstats = NULL;
return err;
}
-
+ dev_hold(dev);
return 0;
}
