From: Eric Dumazet edumazet@google.com
stable inclusion from linux-4.19.191 commit 01cc9ab6fdf1ddb0a5355196557b95819788f9bb
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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@google.com Reported-by: syzbot syzkaller@googlegroups.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- net/ipv6/sit.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-)
diff --git a/net/ipv6/sit.c b/net/ipv6/sit.c index bcf29201f87b3..a629ec46ba3a1 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -215,8 +215,6 @@ static int ipip6_tunnel_create(struct net_device *dev)
ipip6_tunnel_clone_6rd(dev, sitn);
- dev_hold(dev); - ipip6_tunnel_link(sitn, t); return 0;
@@ -1407,7 +1405,7 @@ static int ipip6_tunnel_init(struct net_device *dev) dev->tstats = NULL; return err; } - + dev_hold(dev); return 0; }