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

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>

0 files changed, 0 insertions, 0 deletions