[PATCH 6.12 008/244] driver core: platform: use generic driver_override infrastructure

Greg Kroah-Hartman
2026-03-31T16:47:37Z

From: Danilo Krummrich <dakr@kernel.org>

[ Upstream commit 2b38efc05bf7a8568ec74bfffea0f5cfa62bc01d ]

When a driver is probed through __driver_attach(), the bus' match()
callback is called without the device lock held, thus accessing the
driver_override field without a lock, which can cause a UAF.

Fix this by using the driver-core driver_override infrastructure taking
care of proper locking internally.

Note that calling match() from __driver_attach() without the device lock
held is intentional. [1]

Link: https://lore.kernel.org/driver-core/DGRGTIRHA62X.3RY09D9SOK77P@kernel.org/ [1]
Reported-by: Gui-Dong Han <hanguidong02@gmail.com>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=220789
Fixes: 3d713e0e382e ("driver core: platform: add device binding path 'driver_override'")
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/20260303115720.48783-5-dakr@kernel.org
Signed-off-by: Danilo Krummrich <dakr@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/base/platform.c | 37 +++++----------------------------
drivers/bus/simple-pm-bus.c | 4 ++--
drivers/clk/imx/clk-scu.c | 3 +--
drivers/slimbus/qcom-ngd-ctrl.c | 6 ++----
include/linux/platform_device.h | 5 -----
sound/soc/samsung/i2s.c | 6 +++---
6 files changed, 13 insertions(+), 48 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 6f2a33722c520..24440eec1d4a2 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -562,7 +562,6 @@ static void platform_device_release(struct device *dev)
kfree(pa->pdev.dev.platform_data);
kfree(pa->pdev.mfd_cell);
kfree(pa->pdev.resource);
- kfree(pa->pdev.driver_override);
kfree(pa);
}

@@ -1265,38 +1264,9 @@ static ssize_t numa_node_show(struct device *dev,
}
static DEVICE_ATTR_RO(numa_node);

-static ssize_t driver_override_show(struct device *dev,
- struct device_attribute *attr, char *buf)
-{
- struct platform_device *pdev = to_platform_device(dev);
- ssize_t len;
-
- device_lock(dev);
- len = sysfs_emit(buf, "%s\n", pdev->driver_override);
- device_unlock(dev);
-
- return len;
-}
-
-static ssize_t driver_override_store(struct device *dev,
- struct device_attribute *attr,
- const char *buf, size_t count)
-{
- struct platform_device *pdev = to_platform_device(dev);
- int ret;
-
- ret = driver_set_override(dev, &pdev->driver_override, buf, count);
- if (ret)
- return ret;
-
- return count;
-}
-static DEVICE_ATTR_RW(driver_override);
-
static struct attribute *platform_dev_attrs[] = {
&dev_attr_modalias.attr,
&dev_attr_numa_node.attr,
- &dev_attr_driver_override.attr,
NULL,
};

@@ -1336,10 +1306,12 @@ static int platform_match(struct device *dev, const struct device_driver *drv)
{
struct platform_device *pdev = to_platform_device(dev);
struct platform_driver *pdrv = to_platform_driver(drv);
+ int ret;

/* When driver_override is set, only bind to the matching driver */
- if (pdev->driver_override)
- return !strcmp(pdev->driver_override, drv->name);
+ ret = device_match_driver_override(dev, drv);
+ if (ret >= 0)
+ return ret;

/* Attempt an OF style match first */
if (of_driver_match_device(dev, drv))
@@ -1477,6 +1449,7 @@ static const struct dev_pm_ops platform_dev_pm_ops = {
const struct bus_type platform_bus_type = {
.name = "platform",
.dev_groups = platform_dev_groups,
+ .driver_override = true,
.match = platform_match,
.uevent = platform_uevent,
.probe = platform_probe,
diff --git a/drivers/bus/simple-pm-bus.c b/drivers/bus/simple-pm-bus.c
index 50870c8278899..11fb711edd999 100644
--- a/drivers/bus/simple-pm-bus.c
+++ b/drivers/bus/simple-pm-bus.c
@@ -36,7 +36,7 @@ static int simple_pm_bus_probe(struct platform_device *pdev)
* that's not listed in simple_pm_bus_of_match. We don't want to do any
* of the simple-pm-bus tasks for these devices, so return early.
*/
- if (pdev->driver_override)
+ if (device_has_driver_override(&pdev->dev))
return 0;

match = of_match_device(dev->driver->of_match_table, dev);
@@ -78,7 +78,7 @@ static void simple_pm_bus_remove(struct platform_device *pdev)
{
const void *data = of_device_get_match_data(&pdev->dev);

- if (pdev->driver_override || data)
+ if (device_has_driver_override(&pdev->dev) || data)
return;

dev_dbg(&pdev->dev, "%s\n", __func__);
diff --git a/drivers/clk/imx/clk-scu.c b/drivers/clk/imx/clk-scu.c
index b27186aaf2a15..75a6d91c0711c 100644
--- a/drivers/clk/imx/clk-scu.c
+++ b/drivers/clk/imx/clk-scu.c
@@ -715,8 +715,7 @@ struct clk_hw *imx_clk_scu_alloc_dev(const char *name,
if (ret)
goto put_device;

- ret = driver_set_override(&pdev->dev, &pdev->driver_override,
- "imx-scu-clk", strlen("imx-scu-clk"));
+ ret = device_set_driver_override(&pdev->dev, "imx-scu-clk");
if (ret)
goto put_device;

diff --git a/drivers/slimbus/qcom-ngd-ctrl.c b/drivers/slimbus/qcom-ngd-ctrl.c
index f8d033a289810..ecc74a8903859 100644
--- a/drivers/slimbus/qcom-ngd-ctrl.c
+++ b/drivers/slimbus/qcom-ngd-ctrl.c
@@ -1539,10 +1539,8 @@ static int of_qcom_slim_ngd_register(struct device *parent,
ngd->id = id;
ngd->pdev->dev.parent = parent;

- ret = driver_set_override(&ngd->pdev->dev,
- &ngd->pdev->driver_override,
- QCOM_SLIM_NGD_DRV_NAME,
- strlen(QCOM_SLIM_NGD_DRV_NAME));
+ ret = device_set_driver_override(&ngd->pdev->dev,
+ QCOM_SLIM_NGD_DRV_NAME);
if (ret) {
platform_device_put(ngd->pdev);
kfree(ngd);
diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index 7132623e46585..40f9d2e725bff 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -31,11 +31,6 @@ struct platform_device {
struct resource *resource;

const struct platform_device_id *id_entry;
- /*
- * Driver name to force a match. Do not set directly, because core
- * frees it. Use driver_set_override() to set or clear it.
- */
- const char *driver_override;

/* MFD cell pointer */
struct mfd_cell *mfd_cell;
diff --git a/sound/soc/samsung/i2s.c b/sound/soc/samsung/i2s.c
index 8f6deb06e2346..8ad99f1ef6554 100644
--- a/sound/soc/samsung/i2s.c
+++ b/sound/soc/samsung/i2s.c
@@ -1362,10 +1362,10 @@ static int i2s_create_secondary_device(struct samsung_i2s_priv *priv)
if (!pdev_sec)
return -ENOMEM;

- pdev_sec->driver_override = kstrdup("samsung-i2s", GFP_KERNEL);
- if (!pdev_sec->driver_override) {
+ ret = device_set_driver_override(&pdev_sec->dev, "samsung-i2s");
+ if (ret) {
platform_device_put(pdev_sec);
- return -ENOMEM;
+ return ret;
}

ret = platform_device_add(pdev_sec);
--
2.51.0