[3.16.y-ckt stable] Patch "clocksource: efm32: Fix a NULL pointer dereference" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    clocksource: efm32: Fix a NULL pointer dereference

to the linux-3.16.y-queue branch of the 3.16.y-ckt extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.16.y-queue

This patch is scheduled to be released in version 3.16.7-ckt10.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.16.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From fc28726d892f65d0eb55eb3328ee573deb2c3a26 Mon Sep 17 00:00:00 2001
From: Yongbae Park <yongbae2 at gmail.com>
Date: Tue, 3 Mar 2015 19:46:49 +0900
Subject: clocksource: efm32: Fix a NULL pointer dereference
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

commit 7b8f10da3bf1056546133c9f54f49ce389fd95ab upstream.

The initialisation of the efm32 clocksource first sets up the irq and only
after that initialises the data needed for irq handling. In case this
initialisation is delayed the irq handler would dereference a NULL pointer.

I'm not aware of anything that could delay the process in such a way, but it's
better to be safe than sorry, so setup the irq only when the clock event device
is ready.

Acked-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
Signed-off-by: Yongbae Park <yongbae2 at gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano at linaro.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 drivers/clocksource/time-efm32.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/time-efm32.c b/drivers/clocksource/time-efm32.c
index bba62f9deefb..ec57ba2bbd87 100644
--- a/drivers/clocksource/time-efm32.c
+++ b/drivers/clocksource/time-efm32.c
@@ -225,12 +225,12 @@ static int __init efm32_clockevent_init(struct device_node *np)
 	clock_event_ddata.base = base;
 	clock_event_ddata.periodic_top = DIV_ROUND_CLOSEST(rate, 1024 * HZ);

-	setup_irq(irq, &efm32_clock_event_irq);
-
 	clockevents_config_and_register(&clock_event_ddata.evtdev,
 					DIV_ROUND_CLOSEST(rate, 1024),
 					0xf, 0xffff);

+	setup_irq(irq, &efm32_clock_event_irq);
+
 	return 0;

 err_get_irq: