[PATCH] HID: asus: Add check for cancelling fn_lock_sync_work

[Sahil Chandna <chandna.sahil@gmail.com>]

syzbot reported a workqueue warning where fn_lock_sync_work is cancelled
during device removal before the work has been initialized. This can
happen when the device is disconnected while initialization is still
in progress.
Fix this by initializing fn_lock_sync_work before marking fn_lock as
enabled, and by using fn_lock as a flag in the remove path. This
ensures cancel_work_sync() is only called for initialized work.

Fixes: f631011e36b8 ("HID: hid-asus: Implement fn lock for Asus ProArt P16")
Reported-by: syzbot+13f8286fa2de04a7cd48@syzkaller.appspotmail.com
Signed-off-by: Sahil Chandna <chandna.sahil@gmail.com>
---
 drivers/hid/hid-asus.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
index 1b9793f7c07e..bb85a36de14f 100644
--- a/drivers/hid/hid-asus.c
+++ b/drivers/hid/hid-asus.c
@@ -960,8 +960,8 @@ static int asus_input_configured(struct hid_device *hdev, struct hid_input *hi)
 	}
 
 	if (drvdata->quirks & QUIRK_HID_FN_LOCK) {
-		drvdata->fn_lock = true;
 		INIT_WORK(&drvdata->fn_lock_sync_work, asus_sync_fn_lock);
+		drvdata->fn_lock = true;
 		asus_kbd_set_fn_lock(hdev, true);
 	}
 
@@ -1343,7 +1343,7 @@ static void asus_remove(struct hid_device *hdev)
 		cancel_work_sync(&drvdata->kbd_backlight->work);
 	}
 
-	if (drvdata->quirks & QUIRK_HID_FN_LOCK)
+	if ((drvdata->quirks & QUIRK_HID_FN_LOCK) && drvdata->fn_lock)
 		cancel_work_sync(&drvdata->fn_lock_sync_work);
 
 	hid_hw_stop(hdev);
-- 
2.50.1