From: Eric Dumazet <edumazet@xxxxxxxxxx> commit 764f4eb6846f5475f1244767d24d25dd86528a4a upstream. Whenever llc_ui_bind() and/or llc_ui_autobind() took a reference on a netdevice but subsequently fail, they must properly release their reference or risk the infamous message from unregister_netdevice() at device dismantle. unregister_netdevice: waiting for eth0 to become free. Usage count = 3 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@xxxxxxxxxx> Reported-by: 赵子轩 <beraphin@xxxxxxxxx> Reported-by: Stoyan Manolov <smanolov@xxxxxxx> Link: https://lore.kernel.org/r/20220323004147.1990845-1-eric.dumazet@xxxxxxxxx Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/llc/af_llc.c | 8 ++++++++ 1 file changed, 8 insertions(+) --- a/net/llc/af_llc.c +++ b/net/llc/af_llc.c @@ -311,6 +311,10 @@ static int llc_ui_autobind(struct socket sock_reset_flag(sk, SOCK_ZAPPED); rc = 0; out: + if (rc) { + dev_put(llc->dev); + llc->dev = NULL; + } return rc; } @@ -409,6 +413,10 @@ static int llc_ui_bind(struct socket *so out_put: llc_sap_put(sap); out: + if (rc) { + dev_put(llc->dev); + llc->dev = NULL; + } release_sock(sk); return rc; }