netdev - [PATCH net-next v3 6/7] netvsc: fix error unwind on device setup failure

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Message-Id: <20170728155947.10062-7-sthemmin@microsoft.com>
Date:   Fri, 28 Jul 2017 08:59:46 -0700
From:   Stephen Hemminger <stephen@...workplumber.org>
To:     kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com
Cc:     devel@...uxdriverproject.org, netdev@...r.kernel.org
Subject: [PATCH net-next v3 6/7] netvsc: fix error unwind on device setup failure

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@...rosoft.com>
---
 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
index 4c709b454d34..db95487807fd 100644
--- 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);
-- 
2.11.0