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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Takashi Iwai <tiwai@suse.de>,
        Stephen Hemminger <stephen@networkplumber.org>,
        "David S. Miller" <davem@davemloft.net>,
        Alakesh Haloi <alakeshh@amazon.com>
Subject: [PATCH 4.14 012/173] hv/netvsc: Fix NULL dereference at single queue mode fallback
Date:   Mon, 24 Sep 2018 13:50:46 +0200
Message-Id: <20180924113115.824672422@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@suse.de>

commit b19b46346f483ae055fa027cb2d5c2ca91484b91 upstream.

The recent commit 916c5e1413be ("hv/netvsc: fix handling of fallback
to single queue mode") tried to fix the fallback behavior to a single
queue mode, but it changed the function to return zero incorrectly,
while the function should return an object pointer.  Eventually this
leads to a NULL dereference at the callers that expect non-NULL
value.

Fix it by returning the proper net_device object.

Fixes: 916c5e1413be ("hv/netvsc: fix handling of fallback to single queue mode")
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Cc: Alakesh Haloi <alakeshh@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/net/hyperv/rndis_filter.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1299,7 +1299,7 @@ out:
 	/* setting up multiple channels failed */
 	net_device->max_chn = 1;
 	net_device->num_chn = 1;
-	return 0;
+	return net_device;
 
 err_dev_remv:
 	rndis_filter_device_remove(dev, net_device);