From: Dexuan Cui <decui@microsoft.com>
Date: Thu, 13 Dec 2018 16:35:43 +0000
Patch-mainline: v4.20
Subject: Drivers: hv: vmbus: Return -EINVAL for the sys files for unopened channels
Git-commit: fc96df16a1ce80cbb3c316ab7d4dc8cd5c2852ce
References: bsc#1126389, bsc#1126579, fate#323887

Before 98f4c651762c, we returned zeros for unopened channels.
With 98f4c651762c, we started to return random on-stack values.

We'd better return -EINVAL instead.

Fixes: 98f4c651762c ("hv: move ringbuffer bus attributes to dev_groups")
Cc: stable@vger.kernel.org
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Cc: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Acked-by: Olaf Hering <ohering@suse.de>
---
 drivers/hv/vmbus_drv.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -316,6 +316,8 @@ static ssize_t out_intr_mask_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 	return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 }
@@ -329,6 +331,8 @@ static ssize_t out_read_index_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 	return sprintf(buf, "%d\n", outbound.current_read_index);
 }
@@ -343,6 +347,8 @@ static ssize_t out_write_index_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 	return sprintf(buf, "%d\n", outbound.current_write_index);
 }
@@ -357,6 +363,8 @@ static ssize_t out_read_bytes_avail_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 	return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 }
@@ -371,6 +379,8 @@ static ssize_t out_write_bytes_avail_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound, &outbound);
 	return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 }
@@ -384,6 +394,8 @@ static ssize_t in_intr_mask_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 	return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 }
@@ -397,6 +409,8 @@ static ssize_t in_read_index_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 	return sprintf(buf, "%d\n", inbound.current_read_index);
 }
@@ -410,6 +424,8 @@ static ssize_t in_write_index_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 	return sprintf(buf, "%d\n", inbound.current_write_index);
 }
@@ -424,6 +440,8 @@ static ssize_t in_read_bytes_avail_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 	return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 }
@@ -438,6 +456,8 @@ static ssize_t in_write_bytes_avail_show(struct device *dev,
 
 	if (!hv_dev->channel)
 		return -ENODEV;
+	if (hv_dev->channel->state != CHANNEL_OPENED_STATE)
+		return -EINVAL;
 	hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
 	return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 }