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authorYuhao Jiang <danisjiang@gmail.com>2025-10-22 15:07:04 -0500
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2025-10-23 20:36:55 +0200
commit8f067aa59430266386b83c18b983ca583faa6a11 (patch)
tree226554bec532e49751dde662f3254a0afbabefa7
parent211ddde0823f1442e4ad052a2f30f050145ccada (diff)
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>
-rw-r--r--drivers/acpi/acpi_video.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/acpi/acpi_video.c b/drivers/acpi/acpi_video.c
index 103f29661576..be8e7e18abca 100644
--- a/drivers/acpi/acpi_video.c
+++ b/drivers/acpi/acpi_video.c
@@ -1959,8 +1959,10 @@ 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);