[PATCH] vmbus: don't return values for uninitalized channels

[Stephen Hemminger]

For unsupported device types, the vmbus channel ringbuffer is never
initialized, and therefore reading the sysfs files will return garbage
or cause a kernel OOPS.

Fixes: c2e5df616e1a ("vmbus: add per-channel sysfs info")
Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
---
 drivers/hv/vmbus_drv.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index b10fe26c4891..c9a466be7709 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -1178,6 +1178,9 @@ static ssize_t vmbus_chan_attr_show(struct kobject *kobj,
 	if (!attribute->show)
 		return -EIO;
 
+	if (chan->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
+
 	return attribute->show(chan, buf);
 }
 
-- 
2.18.0