Patch "genirq: Fix chained interrupt data ordering" has been added to the 4.4-stable tree

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

genirq: Fix chained interrupt data ordering

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:
genirq-fix-chained-interrupt-data-ordering.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 <[email protected]> know about it.

From: Thomas Gleixner <[email protected]>
Date: Thu, 11 May 2017 13:54:11 +0200
Subject: genirq: Fix chained interrupt data ordering

From: Thomas Gleixner <[email protected]>

commit 2c4569ca26986d18243f282dd727da27e9adae4c upstream.

irq_set_chained_handler_and_data() sets up the chained interrupt and then stores the handler data.

That's racy against an immediate interrupt which gets handled before the store of the handler data happened. The handler will dereference a NULL pointer and crash.

Cure it by storing handler data before installing the chained handler.

---
 kernel/irq/chip.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -810,8 +810,8 @@ irq_set_chained_handler_and_data(unsigne
 	if (!desc)
 		return;
 
-	__irq_do_set_handler(desc, handle, 1, NULL);
 	desc->irq_common_data.handler_data = data;
+	__irq_do_set_handler(desc, handle, 1, NULL);
 
 	irq_put_desc_busunlock(desc, flags);
 }

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

queue-4.4/stackprotector-increase-the-per-task-stack-canary-s-random-range-from-32-bits-to-64-bits-on-64-bit-platforms.patch queue-4.4/genirq-fix-chained-interrupt-data-ordering.patch queue-4.4/sched-fair-do-not-announce-throttled-next-buddy-in-dequeue_task_fair.patch queue-4.4/sched-fair-initialize-throttle_count-for-new-task-groups-lazily.patch