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s390/ism: add release function for struct device

PATCH Applied Alexandra Winter 3 participants 3 messages Feb 14, 2025 – Feb 18, 2025

Subsystems (4)
Networking Network drivers s390 s390 network drivers
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Alexandra Winter

author maintainer
#0 lore raw

PATCH 1/1 s390/ism: add release function for struct device

From: Julian Ruess <[email protected]>

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 <[email protected]>
Reviewed-by Wenjia Zhang <[email protected]>
Signed-off-by Julian Ruess <[email protected]>
Signed-off-by Alexandra Winter <[email protected]>
---
 drivers/s390/net/ism_drv.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)
drivers/s390/net/ism_drv.c +12 -2
index e36e3ea165d3..2f34761e6413 100644
@@ -588,6 +588,15 @@ static int ism_dev_init(struct ism_dev *ism)
 	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 @@ static int ism_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 	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 = {
Signature · 1 line
2.45.2
reviewer Reviewed-by on v1 1/1
#1 lore raw
Quoted 12 lines · Alexandra Winter

From: Julian Ruess <[email protected]>

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.

Quoted 5 lines
Fixes 8c81ba20349d ("net/smc: De-tangle ism and smc device initialization")
Reviewed-by Alexandra Winter <[email protected]>
Reviewed-by Wenjia Zhang <[email protected]>
Signed-off-by Julian Ruess <[email protected]>
Signed-off-by Alexandra Winter <[email protected]>
Reviewed-by Simon Horman <[email protected]>
CI Applied
#2 lore raw
In reply to Alexandra Winter
This patch was applied to netdev/net.git (main) by Jakub Kicinski <[email protected]>:

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <[email protected]>:

Quoted 6 lines · On Fri, 14 Feb 2025 13:01:37 +0100 you wrote:

From: Julian Ruess <[email protected]>

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

Quoted 7 lines

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.

[...]

Here is the summary with links:
- [net] s390/ism: add release function for struct device

    https://git.kernel.org/netdev/net/c/915e34d5ad35

You are awesome, thank you!

Signature · 2 lines
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