diff mbox series

[c/azure,v2,4/4] Drivers: hv: vmbus: Check for ring when getting debug info

Message ID 20190422202910.32372-5-marcelo.cerri@canonical.com
State New
Headers show
Series Include upstream vmbus fixes to linux-azure | expand

Commit Message

Marcelo Henrique Cerri April 22, 2019, 8:29 p.m. UTC 
From: Dexuan Cui <decui@microsoft.com>

BugLink: http://bugs.launchpad.net/bugs/1821378

fc96df16a1ce is good and can already fix the "return stack garbage" issue,
but let's also improve hv_ringbuffer_get_debuginfo(), which would silently
return stack garbage, if people forget to check channel->state or
ring_info->ring_buffer, when using the function in the future.

Having an error check in the function would eliminate the potential risk.

Add a Fixes tag to indicate the patch depdendency.

Fixes: fc96df16a1ce ("Drivers: hv: vmbus: Return -EINVAL for the sys files for unopened channels")
Cc: stable@vger.kernel.org
Cc: K. Y. Srinivasan <kys@microsoft.com>
Cc: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: Dexuan Cui <decui@microsoft.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
(cherry picked from commit ba50bf1ce9a51fc97db58b96d01306aa70bc3979)
Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri@canonical.com>
---
 drivers/hv/ring_buffer.c | 31 +++++++-------
 drivers/hv/vmbus_drv.c   | 91 +++++++++++++++++++++++++++-------------
 include/linux/hyperv.h   |  5 ++-
 3 files changed, 79 insertions(+), 48 deletions(-)
diff mbox series

Patch

diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 240774e2bc2e..e67ccb108d67 100644
--- a/drivers/hv/ring_buffer.c
+++ b/drivers/hv/ring_buffer.c
@@ -164,26 +164,25 @@  hv_get_ringbuffer_availbytes(const struct hv_ring_buffer_info *rbi,
 }
 
 /* Get various debug metrics for the specified ring buffer. */
-void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
-				 struct hv_ring_buffer_debug_info *debug_info)
+int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
+				struct hv_ring_buffer_debug_info *debug_info)
 {
 	u32 bytes_avail_towrite;
 	u32 bytes_avail_toread;
 
-	if (ring_info->ring_buffer) {
-		hv_get_ringbuffer_availbytes(ring_info,
-					&bytes_avail_toread,
-					&bytes_avail_towrite);
-
-		debug_info->bytes_avail_toread = bytes_avail_toread;
-		debug_info->bytes_avail_towrite = bytes_avail_towrite;
-		debug_info->current_read_index =
-			ring_info->ring_buffer->read_index;
-		debug_info->current_write_index =
-			ring_info->ring_buffer->write_index;
-		debug_info->current_interrupt_mask =
-			ring_info->ring_buffer->interrupt_mask;
-	}
+	if (!ring_info->ring_buffer)
+		return -EINVAL;
+
+	hv_get_ringbuffer_availbytes(ring_info,
+				     &bytes_avail_toread,
+				     &bytes_avail_towrite);
+	debug_info->bytes_avail_toread = bytes_avail_toread;
+	debug_info->bytes_avail_towrite = bytes_avail_towrite;
+	debug_info->current_read_index = ring_info->ring_buffer->read_index;
+	debug_info->current_write_index = ring_info->ring_buffer->write_index;
+	debug_info->current_interrupt_mask
+		= ring_info->ring_buffer->interrupt_mask;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(hv_ringbuffer_get_debuginfo);
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index dff1b632eb56..10c4070a009e 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -297,12 +297,16 @@  static ssize_t out_intr_mask_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info outbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+					  &outbound);
+	if (ret < 0)
+		return ret;
+
 	return sprintf(buf, "%d\n", outbound.current_interrupt_mask);
 }
 static DEVICE_ATTR_RO(out_intr_mask);
@@ -312,12 +316,15 @@  static ssize_t out_read_index_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info outbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+					  &outbound);
+	if (ret < 0)
+		return ret;
 	return sprintf(buf, "%d\n", outbound.current_read_index);
 }
 static DEVICE_ATTR_RO(out_read_index);
@@ -328,12 +335,15 @@  static ssize_t out_write_index_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info outbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+					  &outbound);
+	if (ret < 0)
+		return ret;
 	return sprintf(buf, "%d\n", outbound.current_write_index);
 }
 static DEVICE_ATTR_RO(out_write_index);
@@ -344,12 +354,15 @@  static ssize_t out_read_bytes_avail_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info outbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+					  &outbound);
+	if (ret < 0)
+		return ret;
 	return sprintf(buf, "%d\n", outbound.bytes_avail_toread);
 }
 static DEVICE_ATTR_RO(out_read_bytes_avail);
@@ -360,12 +373,15 @@  static ssize_t out_write_bytes_avail_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info outbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->outbound,
+					  &outbound);
+	if (ret < 0)
+		return ret;
 	return sprintf(buf, "%d\n", outbound.bytes_avail_towrite);
 }
 static DEVICE_ATTR_RO(out_write_bytes_avail);
@@ -375,12 +391,15 @@  static ssize_t in_intr_mask_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info inbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+	if (ret < 0)
+		return ret;
+
 	return sprintf(buf, "%d\n", inbound.current_interrupt_mask);
 }
 static DEVICE_ATTR_RO(in_intr_mask);
@@ -390,12 +409,15 @@  static ssize_t in_read_index_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info inbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+	if (ret < 0)
+		return ret;
+
 	return sprintf(buf, "%d\n", inbound.current_read_index);
 }
 static DEVICE_ATTR_RO(in_read_index);
@@ -405,12 +427,15 @@  static ssize_t in_write_index_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info inbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+	if (ret < 0)
+		return ret;
+
 	return sprintf(buf, "%d\n", inbound.current_write_index);
 }
 static DEVICE_ATTR_RO(in_write_index);
@@ -421,12 +446,15 @@  static ssize_t in_read_bytes_avail_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info inbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+	if (ret < 0)
+		return ret;
+
 	return sprintf(buf, "%d\n", inbound.bytes_avail_toread);
 }
 static DEVICE_ATTR_RO(in_read_bytes_avail);
@@ -437,12 +465,15 @@  static ssize_t in_write_bytes_avail_show(struct device *dev,
 {
 	struct hv_device *hv_dev = device_to_hv_device(dev);
 	struct hv_ring_buffer_debug_info inbound;
+	int ret;
 
 	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);
+
+	ret = hv_ringbuffer_get_debuginfo(&hv_dev->channel->inbound, &inbound);
+	if (ret < 0)
+		return ret;
+
 	return sprintf(buf, "%d\n", inbound.bytes_avail_towrite);
 }
 static DEVICE_ATTR_RO(in_write_bytes_avail);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 89d09b4064a4..2086908b2c8c 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1160,8 +1160,9 @@  struct hv_ring_buffer_debug_info {
 	u32 bytes_avail_towrite;
 };
 
-void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
-			    struct hv_ring_buffer_debug_info *debug_info);
+
+int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,
+				struct hv_ring_buffer_debug_info *debug_info);
 
 /* Vmbus interface */
 #define vmbus_driver_register(driver)	\