From 3c24dbd358bf130da47034ffdb36c4610ed4a92a Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 29 Mar 2021 12:25:22 -0700 Subject: [PATCH] sit: proper dev_{hold|put} in ndo_[un]init methods 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 Reported-by: syzbot Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- 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 146ba7fa..22edda1 100644 --- a/net/ipv6/sit.c +++ b/net/ipv6/sit.c @@ -218,8 +218,6 @@ 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; @@ -1456,7 +1454,7 @@ static int ipip6_tunnel_init(struct net_device *dev) dev->tstats = NULL; return err; } - + dev_hold(dev); return 0; } -- 2.7.4