s390/ism: add release function for struct device

According to device_release() in /drivers/base/core.c,
a device without a release function is a broken device
and must be fixed.

The current code directly frees the device after calling device_add()
without waiting for other kernel parts to release their references.
Thus, a reference could still be held to a struct device,
e.g., by sysfs, leading to potential use-after-free
issues if a proper release function is not set.

Fixes: 8c81ba20349d ("net/smc: De-tangle ism and smc device initialization")
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
Signed-off-by: Julian Ruess <julianr@linux.ibm.com>
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250214120137.563409-1-wintera@linux.ibm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/s390/net/ism_drv.c b/drivers/s390/net/ism_drv.c
index e36e3ea165d3b2b01d68e53634676cb8c2c40220..2f34761e64135c154b5193f870c27753481feed0 100644 (file)
--- a/drivers/s390/net/ism_drv.c
+++ b/drivers/s390/net/ism_drv.c
@@ -588,6 +588,15 @@ out:
        return ret;
 }
 
+static void ism_dev_release(struct device *dev)
+{
+       struct ism_dev *ism;
+
+       ism = container_of(dev, struct ism_dev, dev);
+
+       kfree(ism);
+}
+
 static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 {
        struct ism_dev *ism;
@@ -601,6 +610,7 @@ static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
        dev_set_drvdata(&pdev->dev, ism);
        ism->pdev = pdev;
        ism->dev.parent = &pdev->dev;
+       ism->dev.release = ism_dev_release;
        device_initialize(&ism->dev);
        dev_set_name(&ism->dev, dev_name(&pdev->dev));
        ret = device_add(&ism->dev);
@@ -637,7 +647,7 @@ err:
        device_del(&ism->dev);
 err_dev:
        dev_set_drvdata(&pdev->dev, NULL);
-       kfree(ism);
+       put_device(&ism->dev);
 
        return ret;
 }
@@ -682,7 +692,7 @@ static void ism_remove(struct pci_dev *pdev)
        pci_disable_device(pdev);
        device_del(&ism->dev);
        dev_set_drvdata(&pdev->dev, NULL);
-       kfree(ism);
+       put_device(&ism->dev);
 }
 
 static struct pci_driver ism_driver = {