Patch "clockevents/drivers/cs5535: Improve resilience to spurious interrupts" has been added to the 4.9-stable tree

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

clockevents/drivers/cs5535: Improve resilience to spurious interrupts

to the 4.9-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:
clockevents-drivers-cs5535-improve-resilience-to-spurious-interrupts.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: David Kozub <[email protected]>
Date: Thu, 19 Oct 2017 22:57:02 +0200
Subject: clockevents/drivers/cs5535: Improve resilience to spurious interrupts

From: David Kozub <[email protected]>

commit eb39a7c0355393c5a8d930f342ad7a6231b552c4 upstream.

The interrupt handler mfgpt_tick() is not robust versus spurious interrupts which happen before the clock event device is registered and fully initialized.

The reason is that the safe guard against spurious interrupts solely checks for the clockevents shutdown state, but lacks a check for detached state. If the interrupt hits while the device is in detached state it passes the safe guard and dereferences the event handler call back which is NULL.

Add the missing state check.

---
 drivers/clocksource/cs5535-clockevt.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -117,7 +117,8 @@ static irqreturn_t mfgpt_tick(int irq, v
 	/* Turn off the clock (and clear the event) */
 	disable_timer(cs5535_event_clock);
 
-	if (clockevent_state_shutdown(&cs5535_clockevent))
+	if (clockevent_state_detached(&cs5535_clockevent) ||
+	    clockevent_state_shutdown(&cs5535_clockevent))
 		return IRQ_HANDLED;
 
 	/* Clear the counter */

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/clockevents-drivers-cs5535-improve-resilience-to-spurious-interrupts.patch