From 0f20d795f78d182c4b743d880a5e8dc4d39892fe Mon Sep 17 00:00:00 2001 From: Vitaly Kuznetsov Date: Mon, 15 Aug 2016 17:48:42 +0200 Subject: [PATCH] hv_netvsc: protect module refcount by checking net_device_ctx->vf_netdev We're not guaranteed to see NETDEV_REGISTER/NETDEV_UNREGISTER notifications only once per VF but we increase/decrease module refcount unconditionally. Check vf_netdev to make sure we don't take/release it twice. We presume that only one VF per netvsc device may exist. Signed-off-by: Vitaly Kuznetsov Acked-by: Haiyang Zhang Signed-off-by: David S. Miller --- drivers/net/hyperv/netvsc_drv.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c index 2c90883d089e..62a4e6e3c63e 100644 --- a/drivers/net/hyperv/netvsc_drv.c +++ b/drivers/net/hyperv/netvsc_drv.c @@ -1193,7 +1193,7 @@ static int netvsc_register_vf(struct net_device *vf_netdev) net_device_ctx = netdev_priv(ndev); netvsc_dev = net_device_ctx->nvdev; - if (netvsc_dev == NULL) + if (!netvsc_dev || net_device_ctx->vf_netdev) return NOTIFY_DONE; netdev_info(ndev, "VF registering: %s\n", vf_netdev->name); @@ -1312,7 +1312,7 @@ static int netvsc_unregister_vf(struct net_device *vf_netdev) net_device_ctx = netdev_priv(ndev); netvsc_dev = net_device_ctx->nvdev; - if (netvsc_dev == NULL) + if (!netvsc_dev || !net_device_ctx->vf_netdev) return NOTIFY_DONE; netdev_info(ndev, "VF unregistering: %s\n", vf_netdev->name); netvsc_inject_disable(net_device_ctx);