e1000: fix possible reset_task running after adapter down

On e1000_down(), we should ensure every asynchronous work is canceled before proceeding. Since the watchdog_task can schedule other works apart from itself, it should be stopped first, but currently it is stopped after the reset_task. This can result in the following race leading to the reset_task running after the module unload: e1000_down_and_stop(): e1000_watchdog(): ---------------------- ----------------- cancel_work_sync(reset_task) schedule_work(reset_task) cancel_delayed_work_sync(watchdog_task) The patch moves cancel_delayed_work_sync(watchdog_task) at the beginning of e1000_down_and_stop() thus ensuring the race is impossible. Cc: Tushar Dave <[email protected]> Cc: Patrick McHardy <[email protected]> Signed-off-by: Vladimir Davydov <[email protected]> Tested-by: Aaron Brown <[email protected]> Signed-off-by: Jeff Kirsher <[email protected]>
kyagi · Nov 30, 2013 · 74a1b1e · 74a1b1e
1 parent b2f963b
commit 74a1b1e
Showing 1 changed file with 11 additions and 4 deletions.
diff --git a/drivers/net/ethernet/intel/e1000/e1000_main.c b/drivers/net/ethernet/intel/e1000/e1000_main.c
@@ -494,13 +494,20 @@ static void e1000_down_and_stop(struct e1000_adapter *adapter)
 {
 	set_bit(__E1000_DOWN, &adapter->flags);
 
-	/* Only kill reset task if adapter is not resetting */
-	if (!test_bit(__E1000_RESETTING, &adapter->flags))
-		cancel_work_sync(&adapter->reset_task);
-
 	cancel_delayed_work_sync(&adapter->watchdog_task);
+
+	/*
+	 * Since the watchdog task can reschedule other tasks, we should cancel
+	 * it first, otherwise we can run into the situation when a work is
+	 * still running after the adapter has been turned down.
+	 */
+
 	cancel_delayed_work_sync(&adapter->phy_info_task);
 	cancel_delayed_work_sync(&adapter->fifo_stall_task);
+
+	/* Only kill reset task if adapter is not resetting */
+	if (!test_bit(__E1000_RESETTING, &adapter->flags))
+		cancel_work_sync(&adapter->reset_task);
 }
 
 void e1000_down(struct e1000_adapter *adapter)