6.4-stable review patch. If anyone has any objections, please let me know.
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From: David Gow davidgow@google.com
[ 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 davidgow@google.com Signed-off-by: Maxime Ripard mripard@kernel.org Link: https://lore.kernel.org/r/20230720-kunit-devm-inconsistencies-test-v3-3-6aa7... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/core.c | 11 +++++++++++ 1 file changed, 11 insertions(+)
diff --git a/drivers/base/core.c b/drivers/base/core.c index 3dff5037943e0..6ceaf50f5a671 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);