clocksource: efm32: Fix a NULL pointer dereference

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@pengutronix.de>
Signed-off-by: Yongbae Park <yongbae2@gmail.com>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/clocksource/time-efm32.c b/drivers/clocksource/time-efm32.c
index bba62f9deefbd0f71d59409daf85857cc2caa983..ec57ba2bbd87ac9f2a251e350598fa52019d7815 100644 (file)
--- 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: