From: David Gow <davidgow@google.com> mainline inclusion from mainline-v6.6-rc1 commit 699fb50d99039a50e7494de644f96c889279aca3 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/8116 CVE: CVE-2023-53596 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- 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> Conflicts: drivers/base/core.c drivers/base/test/platform-device-test.c drivers/base/test/root-device-test.c [context conflicts: platform-device-test.c and root-device-test.c do not exist. ed9f918174cb "driver core: bus: move bus notifier logic into bus.c" not merged] Signed-off-by: Chen Jun <chenjun102@huawei.com> --- drivers/base/core.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/base/core.c b/drivers/base/core.c index eb82b43181be..81889d8ccbd1 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3210,6 +3210,17 @@ 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); -- 2.22.0