From: David Gow davidgow@google.com
In the current code, devres_release_all() only gets called if the device has a bus and has been probed.
This leads to issues when using bus-less or driver-less devices where the device might never get freed if a managed resource holds a reference to the device. This is happening in the DRM framework for example.
We should thus call devres_release_all() in the device_del() function to make sure that the device-managed actions are properly executed when the device is unregistered, even if it has neither a bus nor a driver.
This is effectively the same change than commit 2f8d16a996da ("devres: release resources on device_del()") that got reverted by commit a525a3ddeaca ("driver core: free devres in device_release") over use-after-free concerns.
It's not clear whether those concerns are legitimate though, but I would expect drivers not to register new resources in their device-managed actions.
Fixes: a525a3ddeaca ("driver core: free devres in device_release") Signed-off-by: Maxime Ripard mripard@kernel.org --- drivers/base/core.c | 11 +++++++++++ drivers/base/test/platform-device-test.c | 2 -- drivers/base/test/root-device-test.c | 2 -- 3 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/base/core.c b/drivers/base/core.c index 3dff5037943e..6ceaf50f5a67 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3817,6 +3817,17 @@ void device_del(struct device *dev) device_platform_notify_remove(dev); device_links_purge(dev);
+ /* + * If a device does not have a driver attached, we need to clean + * up any managed resources. We do this in device_release(), but + * it's never called (and we leak the device) if a managed + * resource holds a reference to the device. So release all + * managed resources here, like we do in driver_detach(). We + * still need to do so again in device_release() in case someone + * adds a new resource after this point, though. + */ + devres_release_all(dev); + bus_notify(dev, BUS_NOTIFY_REMOVED_DEVICE); kobject_uevent(&dev->kobj, KOBJ_REMOVE); glue_dir = get_glue_dir(dev); diff --git a/drivers/base/test/platform-device-test.c b/drivers/base/test/platform-device-test.c index b6ebf1dcdffb..1ae5ce8bd366 100644 --- a/drivers/base/test/platform-device-test.c +++ b/drivers/base/test/platform-device-test.c @@ -87,8 +87,6 @@ static void platform_device_devm_register_get_unregister_with_devm_test(struct k struct test_priv *priv = test->priv; int ret;
- kunit_skip(test, "This needs to be fixed in the core."); - pdev = platform_device_alloc(DEVICE_NAME, PLATFORM_DEVID_NONE); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, pdev);
diff --git a/drivers/base/test/root-device-test.c b/drivers/base/test/root-device-test.c index 9a3e6cccae13..780d07455f57 100644 --- a/drivers/base/test/root-device-test.c +++ b/drivers/base/test/root-device-test.c @@ -78,8 +78,6 @@ static void root_device_devm_register_get_unregister_with_devm_test(struct kunit struct test_priv *priv = test->priv; int ret;
- kunit_skip(test, "This needs to be fixed in the core."); - priv->dev = root_device_register(DEVICE_NAME); KUNIT_ASSERT_NOT_ERR_OR_NULL(test, priv->dev);