From 6bab4a8a1888729f17f4923cc5867e4674f66333 Mon Sep 17 00:00:00 2001 From: Maxime Ripard Date: Tue, 18 Nov 2014 23:59:33 +0100 Subject: [PATCH] clockevent: sun4i: Fix race condition in the probe code 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 Signed-off-by: Maxime Ripard Cc: stable@vger.kernel.org Signed-off-by: Daniel Lezcano --- drivers/clocksource/sun4i_timer.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/drivers/clocksource/sun4i_timer.c b/drivers/clocksource/sun4i_timer.c index efb17c3ee120..f4a9c0058b4d 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-a10-timer", sun4i_timer_init);