Patch "genirq: Fix chained interrupt data ordering" has been added to the 4.9-stable tree

Patch "genirq: Fix chained interrupt data ordering" has been added to the 4.9-stable tree

[gregkh]

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

    genirq: Fix chained interrupt data ordering

to the 4.9-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:
     genirq-fix-chained-interrupt-data-ordering.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 <stable@vger.kernel.org> know about it.


>From 2c4569ca26986d18243f282dd727da27e9adae4c Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 11 May 2017 13:54:11 +0200
Subject: genirq: Fix chained interrupt data ordering

From: Thomas Gleixner <tglx@linutronix.de>

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.

Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -877,8 +877,8 @@ 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 tglx@linutronix.de are

queue-4.9/stackprotector-increase-the-per-task-stack-canary-s-random-range-from-32-bits-to-64-bits-on-64-bit-platforms.patch
queue-4.9/genirq-fix-chained-interrupt-data-ordering.patch