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ACPI: video: Fix use-after-free in acpi_video_switch_brightness()

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commit 8f067aa594 upstream.

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: 8ab58e8e7e ("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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Yuhao Jiang
2025-11-24 10:29:11 +01:00
committed by Greg Kroah-Hartman
parent 3fe5494db5
commit 4e85246ec0
1 changed files with 3 additions and 1 deletions
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drivers/acpi/acpi_video.c
+3 -1
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@@ -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);