can: bcm: fix hrtimer/tasklet termination in bcm op removal

hartkopp · marckleinebudde · commit a06393ed0316 · 2017-01-30T11:05:04.000+01:00
When removing a bcm tx operation either a hrtimer or a tasklet might run.
As the hrtimer triggers its associated tasklet and vice versa we need to
take care to mutually terminate both handlers.

Reported-by: Michael Josenhans &lt;michael.josenhans@web.de&gt;
Signed-off-by: Oliver Hartkopp &lt;socketcan@hartkopp.net&gt;
Tested-by: Michael Josenhans &lt;michael.josenhans@web.de&gt;
Cc: linux-stable &lt;stable@vger.kernel.org&gt;
Signed-off-by: Marc Kleine-Budde &lt;mkl@pengutronix.de&gt;
diff --git a/net/can/bcm.c b/net/can/bcm.c
@@ -734,14 +734,23 @@ static struct bcm_op *bcm_find_op(struct list_head *ops,
 
 static void bcm_remove_op(struct bcm_op *op)
 {
-	hrtimer_cancel(&op->timer);
-	hrtimer_cancel(&op->thrtimer);
-
-	if (op->tsklet.func)
-		tasklet_kill(&op->tsklet);
+	if (op->tsklet.func) {
+		while (test_bit(TASKLET_STATE_SCHED, &op->tsklet.state) ||
+		       test_bit(TASKLET_STATE_RUN, &op->tsklet.state) ||
+		       hrtimer_active(&op->timer)) {
+			hrtimer_cancel(&op->timer);
+			tasklet_kill(&op->tsklet);
+		}
+	}
 
-	if (op->thrtsklet.func)
-		tasklet_kill(&op->thrtsklet);
+	if (op->thrtsklet.func) {
+		while (test_bit(TASKLET_STATE_SCHED, &op->thrtsklet.state) ||
+		       test_bit(TASKLET_STATE_RUN, &op->thrtsklet.state) ||
+		       hrtimer_active(&op->thrtimer)) {
+			hrtimer_cancel(&op->thrtimer);
+			tasklet_kill(&op->thrtsklet);
+		}
+	}
 
 	if ((op->frames) && (op->frames != &op->sframe))
 		kfree(op->frames);
