From: stephen hemminger <stephen@networkplumber.org>
Date: Fri, 28 Jul 2017 08:59:46 -0700
Patch-mainline: v4.14-rc1
Subject: netvsc: fix error unwind on device setup failure
Git-commit: 493933472d33d3e82d6323842edeb281199ee430
References: fate#323887

If setting receive buffer fails, the error unwind would cause
kernel panic because it was not correctly doing RCU and NAPI
unwind.  RCU'd pointer needs to be reset to NULL, and NAPI needs
to be disabled not deleted.

Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Olaf Hering <ohering@suse.de>
---
 drivers/net/hyperv/netvsc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hyperv/netvsc.c b/drivers/net/hyperv/netvsc.c
--- a/drivers/net/hyperv/netvsc.c
+++ b/drivers/net/hyperv/netvsc.c
@@ -1307,7 +1307,8 @@ struct netvsc_device *netvsc_device_add(struct hv_device *device,
 	return net_device;
 
 close:
-	netif_napi_del(&net_device->chan_table[0].napi);
+	RCU_INIT_POINTER(net_device_ctx->nvdev, NULL);
+	napi_disable(&net_device->chan_table[0].napi);
 
 	/* Now, we can close the channel safely */
 	vmbus_close(device->channel);