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: sta...@vger.kernel.org
Cc: K. Y. Srinivasan <k...@microsoft.com>
Cc: Haiyang Zhang <haiya...@microsoft.com>
Signed-off-by: Stephen Hemminger <sthem...@microsoft.com>
Signed-off-by: Dexuan Cui <de...@microsoft.com>
---
*NOTE*: the patch is based on char-misc's char-misc-linus branch.
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 --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c
index 64d0c85..1f1a55e 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 d0ff656..403fee0 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -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);
diff --git a/include/linux/hyperv.h b/include/linux/hyperv.h
index 14131b6..ed74888 100644
--- a/include/linux/hyperv.h
+++ b/include/linux/hyperv.h
@@ -1176,8 +1176,9 @@ 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) \
--
2.7.4
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