[PATCH 3.16.y-ckt 016/144] clocksource: efm32: Fix a NULL pointer dereference

[Luis Henriques]

3.16.7-ckt10 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yongbae Park <yongbae2@xxxxxxxxx>

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-KÃnig <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Yongbae Park <yongbae2@xxxxxxxxx>
Signed-off-by: Daniel Lezcano <daniel.lezcano@xxxxxxxxxx>
Signed-off-by: Luis Henriques <luis.henriques@xxxxxxxxxxxxx>
---
 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:
--
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