From: Yuhao Jiang <danisjiang@gmail.com> mainline inclusion from mainline-v6.18-rc4 commit 8f067aa59430266386b83c18b983ca583faa6a11 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/ID7X34 CVE: CVE-2025-40211 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- The switch_brightness_work delayed work accesses device->brightness and device->backlight, freed by acpi_video_dev_unregister_backlight() during device removal. If the work executes after acpi_video_bus_unregister_backlight() frees these resources, it causes a use-after-free when acpi_video_switch_brightness() dereferences device->brightness or device->backlight. Fix this by calling cancel_delayed_work_sync() for each device's switch_brightness_work in acpi_video_bus_remove_notify_handler() after removing the notify handler that queues the work. This ensures the work completes before the memory is freed. Fixes: 8ab58e8e7e097 ("ACPI / video: Fix backlight taking 2 steps on a brightness up/down keypress") Cc: All applicable <stable@vger.kernel.org> Signed-off-by: Yuhao Jiang <danisjiang@gmail.com> Reviewed-by: Hans de Goede <hansg@kernel.org> [ rjw: Changelog edit ] Link: https://patch.msgid.link/20251022200704.2655507-1-danisjiang@gmail.com Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Bowen You <youbowen2@huawei.com> --- drivers/acpi/acpi_video.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c index a971770e24ff..841db33e9475 100644 --- a/drivers/acpi/acpi_video.c +++ b/drivers/acpi/acpi_video.c @@ -1952,8 +1952,10 @@ static void acpi_video_bus_remove_notify_handler(struct acpi_video_bus *video) struct acpi_video_device *dev; mutex_lock(&video->device_list_lock); - list_for_each_entry(dev, &video->video_device_list, entry) + list_for_each_entry(dev, &video->video_device_list, entry) { acpi_video_dev_remove_notify_handler(dev); + cancel_delayed_work_sync(&dev->switch_brightness_work); + } mutex_unlock(&video->device_list_lock); acpi_video_bus_stop_devices(video); -- 2.34.1