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authorMaxime Ripard <maxime.ripard@free-electrons.com>2014-11-18 23:59:33 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-12-06 15:55:34 -0800
commit09c5db4f301e49dfe70afc8401d3f15c2cfecd68 (patch)
treece6e44859acf372472f5997a47d09bb544dbab04
parent2c120e85dea7358d2255cf68b2fd2b666077c768 (diff)
clockevent: sun4i: Fix race condition in the probe code
commit 6bab4a8a1888729f17f4923cc5867e4674f66333 upstream. The interrupts were activated and the handler registered before the clockevent was registered in the probe function. The interrupt handler, however, was making the assumption that the clockevent device was registered. That could cause a null pointer dereference if the timer interrupt was firing during this narrow window. Fix that by moving the clockevent registration before the interrupt is enabled. Reported-by: Roman Byshko <rbyshko@gmail.com> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/clocksource/sun4i_timer.c12
1 files changed, 6 insertions, 6 deletions
diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c
index bf497afba9ad..7d19f86012f2 100644
--- a/drivers/clocksource/sun4i_timer.c
+++ b/drivers/clocksource/sun4i_timer.c
@@ -182,6 +182,12 @@ static void __init sun4i_timer_init(struct device_node *node)
/* Make sure timer is stopped before playing with interrupts */
sun4i_clkevt_time_stop(0);
+ sun4i_clockevent.cpumask = cpu_possible_mask;
+ sun4i_clockevent.irq = irq;
+
+ clockevents_config_and_register(&sun4i_clockevent, rate,
+ TIMER_SYNC_TICKS, 0xffffffff);
+
ret = setup_irq(irq, &sun4i_timer_irq);
if (ret)
pr_warn("failed to setup irq %d\n", irq);
@@ -189,12 +195,6 @@ static void __init sun4i_timer_init(struct device_node *node)
/* Enable timer0 interrupt */
val = readl(timer_base + TIMER_IRQ_EN_REG);
writel(val | TIMER_IRQ_EN(0), timer_base + TIMER_IRQ_EN_REG);
-
- sun4i_clockevent.cpumask = cpu_possible_mask;
- sun4i_clockevent.irq = irq;
-
- clockevents_config_and_register(&sun4i_clockevent, rate,
- TIMER_SYNC_TICKS, 0xffffffff);
}
CLOCKSOURCE_OF_DECLARE(sun4i, "allwinner,sun4i-timer",
sun4i_timer_init);