From b9ef4b0aa91d2f9f5951faafdbbd47cf01799ec3 Mon Sep 17 00:00:00 2001 From: David Gow Date: Tue, 24 Mar 2026 16:14:38 +0800 Subject: [PATCH] drivers: base: Free devm resources when unregistering a device [ Upstream commit 699fb50d99039a50e7494de644f96c889279aca3 ] 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 memory leaks concerns. This patch effectively combines the two commits mentioned above to release the resources both on device_del() and device_release() and get the best of both worlds. Fixes: a525a3ddeaca ("driver core: free devres in device_release") Signed-off-by: David Gow Signed-off-by: Maxime Ripard Link: https://lore.kernel.org/r/20230720-kunit-devm-inconsistencies-test-v3-3-6aa7e074f373@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Li hongliang <1468888505@139.com> Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index 4fc62624a95e..683a7c461451 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3604,9 +3604,21 @@ void device_del(struct device *dev) device_remove_properties(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); + if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_REMOVED_DEVICE, dev); + kobject_uevent(&dev->kobj, KOBJ_REMOVE); glue_dir = get_glue_dir(dev); kobject_del(&dev->kobj);