On 7/14/26 6:01 AM, Simon Horman wrote:
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Full review at: https://sashiko.dev
---
ibmveth: Expose per-queue buffer pool details via sysfs
This commit adds a read-only sysfs attribute buffer_pools to the VIO device
to expose per-queue buffer pool details dynamically. It outputs runtime
per-queue
buffer pressure metrics like size, active, and available buffers.
diff --git a/drivers/net/ethernet/ibm/ibmveth.c
b/drivers/net/ethernet/ibm/ibmveth.c
index 4e3f49b6346fd..ecc472ee8f71f 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -2896,6 +2896,52 @@ static const struct net_device_ops ibmveth_netdev_ops = {
[ ... ]
+static ssize_t buffer_pools_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct net_device *netdev = dev_get_drvdata(dev);
+ struct ibmveth_adapter *adapter = netdev_priv(netdev);
+ int len = 0;
+ int i, j;
+
+ len += scnprintf(buf + len, PAGE_SIZE - len,
+ "Queue Pool Size BuffSize Active Available\n");
+ len += scnprintf(buf + len, PAGE_SIZE - len,
+ "----- ---- ---- -------- ------ ---------\n");
[Severity: Medium]
Does this buffer_pools_show() implementation violate the sysfs "one value
per file" design rule?
The attribute appears to dump a complex, multi-line ASCII table with headers
and columns rather than exposing a single value per sysfs file.
*
Agreed this is more of a diagnostic dump than a sysfs one-value
attribute. In v4 I’ll move it to debugfs ?
*
[ ... ]
@@ -3056,6 +3102,14 @@ static int ibmveth_probe(struct vio_dev *dev, const
struct vio_device_id *id)
netdev_dbg(netdev, "registered\n");
+ rc = sysfs_create_group(&dev->dev.kobj, &ibmveth_attr_group);
+ if (rc) {
+ netdev_err(netdev, "failed to create sysfs attributes rc=%d\n",
rc);
+ unregister_netdev(netdev);
+ free_netdev(netdev);
+ return rc;
+ }
[Severity: High]
If userspace brings up the interface immediately after register_netdev()
succeeds, could adapter->work be scheduled before sysfs_create_group() fails?
If this race occurs, unregister_netdev() does not synchronously cancel the
work.
Could the global workqueue execute the pending adapter->work item on freed
memory after free_netdev() is called in this ibmveth_probe() error path?
*
Good catch. remove() cancels the work, but this probe error path
did not. Will cancel_work_sync() (and clean pool kobjects) before
free_netdev() in v4.
*
[Severity: High]
This is a pre-existing issue in older error paths of ibmveth_probe(), but it
is duplicated here: does this error path leak the adapter->rx_buff_pool
kobjects?
Since kobject_put() is not called on the pool kobjects before free_netdev()
is executed, the kobjects remain attached to the VIO device with dangling
pointers to the freed adapter memory.
Could subsequent sysfs accesses to those pool kobjects trigger a
use-after-free?
*
Yes — that path (and some older probe failure paths) skip
kobject_put() on the pool objects. I’ll add a common probe
cleanup helper in v4 so pool kobjects and the reset work are
always torn down before free_netdev().
*
Thanks,
Mingming
