Bluetooth: virtio_bt: add missing null pointer check on alloc_skb call return

The call to alloc_skb with the GFP_KERNEL flag can return a null sk_buff
pointer, so add a null check to avoid any null pointer deference issues.

Addresses-Coverity: ("Dereference null return value")
Fixes: afd2daa2 ("Bluetooth: Add support for virtio transport driver")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>

drivers/bluetooth/virtio_bt.c

@@ -34,6 +34,9 @@ static int virtbt_add_inbuf(struct virtio_bluetooth *vbt)
 	int err;
 
 	skb = alloc_skb(1000, GFP_KERNEL);
+	if (!skb)
+		return -ENOMEM;
+
 	sg_init_one(sg, skb->data, 1000);
 
 	err = virtqueue_add_inbuf(vq, sg, 1, skb, GFP_KERNEL);