netvsc: fix rtnl deadlock on unregister of vf

With new transparent VF support, it is possible to get a deadlock
when some of the deferred work is running and the unregister_vf
is trying to cancel the work element. The solution is to use
trylock and reschedule (similar to bonding and team device).

Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Fixes: 0c195567a8 ("netvsc: transparent VF management")
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
stephen hemminger 2017-08-04 12:14:00 -07:00 committed by David S. Miller
parent 5f6b4e14ca
commit fb84af8a43

View File

@ -1601,7 +1601,11 @@ static void netvsc_vf_setup(struct work_struct *w)
struct net_device *ndev = hv_get_drvdata(ndev_ctx->device_ctx);
struct net_device *vf_netdev;
rtnl_lock();
if (!rtnl_trylock()) {
schedule_work(w);
return;
}
vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
if (vf_netdev)
__netvsc_vf_setup(ndev, vf_netdev);
@ -1655,7 +1659,11 @@ static void netvsc_vf_update(struct work_struct *w)
struct net_device *vf_netdev;
bool vf_is_up;
rtnl_lock();
if (!rtnl_trylock()) {
schedule_work(w);
return;
}
vf_netdev = rtnl_dereference(ndev_ctx->vf_netdev);
if (!vf_netdev)
goto unlock;