Patch "can: bcm: fix hrtimer/tasklet termination in bcm op removal" has been added to the 4.4-stable tree

[<gregkh@linuxfoundation.org>]

This is a note to let you know that I've just added the patch titled

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

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     can-bcm-fix-hrtimer-tasklet-termination-in-bcm-op-removal.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From a06393ed03167771246c4c43192d9c264bc48412 Mon Sep 17 00:00:00 2001
From: Oliver Hartkopp <socketcan@hartkopp.net>
Date: Wed, 18 Jan 2017 21:30:51 +0100
Subject: can: bcm: fix hrtimer/tasklet termination in bcm op removal

From: Oliver Hartkopp <socketcan@hartkopp.net>

commit a06393ed03167771246c4c43192d9c264bc48412 upstream.

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 <michael.josenhans@web.de>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Tested-by: Michael Josenhans <michael.josenhans@web.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 net/can/bcm.c |   23 ++++++++++++++++-------
 1 file changed, 16 insertions(+), 7 deletions(-)

--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -710,14 +710,23 @@ static struct bcm_op *bcm_find_op(struct
 
 static void bcm_remove_op(struct bcm_op *op)
 {
-	hrtimer_cancel(&op->timer);
-	hrtimer_cancel(&op->thrtimer);
+	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->tsklet.func)
-		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);


Patches currently in stable-queue which might be from socketcan@hartkopp.net are

queue-4.4/can-bcm-fix-hrtimer-tasklet-termination-in-bcm-op-removal.patch