wifi: mwifiex: fix use-after-free in mwifiex_adapter_cleanup()

The mwifiex_adapter_cleanup() function uses timer_delete() (non-synchronous) for the wakeup_timer before the adapter structure is freed. This is incorrect because timer_delete() does not wait for any running timer callback to complete.

If the wakeup_timer callback (wakeup_timer_fn) is executing when mwifiex_adapter_cleanup() is called, the callback will continue to access adapter fields (adapter->hw_status, adapter->if_ops.card_reset, etc.) which may be freed by mwifiex_free_adapter() called later in the mwifiex_remove_card() path.

Use timer_delete_sync() instead to ensure any running timer callback has completed before returning.

---
 drivers/net/wireless/marvell/mwifiex/init.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

index 4820010a86f6..5902e2c821f2 100644
@@ -391,7 +391,7 @@ static void mwifiex_invalidate_lists(struct mwifiex_adapter *adapter)
 static void
 mwifiex_adapter_cleanup(struct mwifiex_adapter *adapter)
 {
-	timer_delete(&adapter->wakeup_timer);
+	timer_delete_sync(&adapter->wakeup_timer);
 	cancel_delayed_work_sync(&adapter->devdump_work);
 	mwifiex_cancel_all_pending_cmd(adapter);
 	wake_up_interruptible(&adapter->cmd_wait_q.wait);

2.52.0