Commit ba50bf1c authored by Dexuan Cui's avatar Dexuan Cui Committed by Sasha Levin
Browse files

Drivers: hv: vmbus: Check for ring when getting debug info 



fc96df16 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: fc96df16 ("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: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent bfeffd15

drivers/hv/ring_buffer.c

+15 −16
Original line number Diff line number Diff line
@@ -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,

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) {

	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;

	}

	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);

drivers/hv/vmbus_drv.c

+61 −30
Original line number Diff line number Diff line
@@ -313,12 +313,16 @@ 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);
@@ -328,12 +332,15 @@ 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);
@@ -344,12 +351,15 @@ 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);
@@ -360,12 +370,15 @@ 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);
@@ -376,12 +389,15 @@ 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);
@@ -391,12 +407,15 @@ 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);
@@ -406,12 +425,15 @@ 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);
@@ -421,12 +443,15 @@ 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);
@@ -437,12 +462,15 @@ 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);
@@ -453,12 +481,15 @@ 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);

include/linux/hyperv.h

+3 −2
Original line number Diff line number Diff line
@@ -1159,7 +1159,8 @@ struct hv_ring_buffer_debug_info { 
	u32 bytes_avail_towrite;

};



void hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,



int hv_ringbuffer_get_debuginfo(const struct hv_ring_buffer_info *ring_info,

				struct hv_ring_buffer_debug_info *debug_info);



/* Vmbus interface */

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