If VF NIC is registered earlier, NETDEV_REGISTER event is replayed,
but NETDEV_POST_INIT is not.

Move register_netdevice_notifier() earlier, so the call back
function is set before probing.

Cc: stable@vger.kernel.org
Fixes: e04e7a7bbd4b ("hv_netvsc: Fix a deadlock by getting rtnl lock earlier in netvsc_probe()")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Wojciech Drewek <wojciech.drewek@intel.com>

---
v3:
  Divide it into two patches, suggested by Jakub Kicinski.

v2:
  Fix rtnl_unlock() in error handling as found by Wojciech Drewek.
---
 drivers/net/hyperv/netvsc_drv.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 5e528a76f5f5..1d1491da303b 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -2793,11 +2793,14 @@ static int __init netvsc_drv_init(void)
 	}
 	netvsc_ring_bytes = ring_size * PAGE_SIZE;
 
+	register_netdevice_notifier(&netvsc_netdev_notifier);
+
 	ret = vmbus_driver_register(&netvsc_drv);
-	if (ret)
+	if (ret) {
+		unregister_netdevice_notifier(&netvsc_netdev_notifier);
 		return ret;
+	}
 
-	register_netdevice_notifier(&netvsc_netdev_notifier);
 	return 0;
 }
 
-- 
2.25.1

On Tue,  7 Nov 2023 13:05:32 -0800 Haiyang Zhang wrote:
> If VF NIC is registered earlier, NETDEV_REGISTER event is replayed,
> but NETDEV_POST_INIT is not.

But Long Li sent the patch which starts to use POST_INIT against 
the net-next tree. If we apply this to net and Long Li's patch to
net-next one release will have half of the fixes.

I think that you should add Long Li's patch to this series. That'd
limit the confusion and git preserves authorship of the changes, so
neither of you will loose the credit.

> -----Original Message-----
> From: Jakub Kicinski <kuba@kernel.org>
> Sent: Wednesday, November 8, 2023 9:26 PM
> To: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; KY Srinivasan
> <kys@microsoft.com>; wei.liu@kernel.org; Dexuan Cui
> <decui@microsoft.com>; edumazet@google.com; pabeni@redhat.com;
> davem@davemloft.net; linux-kernel@vger.kernel.org; stable@vger.kernel.org
> Subject: Re: [PATCH net,v3, 2/2] hv_netvsc: Fix race of
> register_netdevice_notifier and VF register
> 
> On Tue,  7 Nov 2023 13:05:32 -0800 Haiyang Zhang wrote:
> > If VF NIC is registered earlier, NETDEV_REGISTER event is replayed,
> > but NETDEV_POST_INIT is not.
> 
> But Long Li sent the patch which starts to use POST_INIT against
> the net-next tree. If we apply this to net and Long Li's patch to
> net-next one release will have half of the fixes.
> 
> I think that you should add Long Li's patch to this series. That'd
> limit the confusion and git preserves authorship of the changes, so
> neither of you will loose the credit.

Will do.

Thanks,
- Haiyang