From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932850AbaKRXAG (ORCPT ); Tue, 18 Nov 2014 18:00:06 -0500 Received: from down.free-electrons.com ([37.187.137.238]:34444 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932648AbaKRXAE (ORCPT ); Tue, 18 Nov 2014 18:00:04 -0500 From: Maxime Ripard To: Daniel Lezcano , Thomas Gleixner Cc: linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Roman Byshko , Maxime Ripard , stable@vger.kernel.org Subject: [PATCH] clockevent: sun4i: Fix race condition in the probe code Date: Tue, 18 Nov 2014 23:59:33 +0100 Message-Id: <1416351573-5815-1-git-send-email-maxime.ripard@free-electrons.com> X-Mailer: git-send-email 2.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 dereferenc 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 --- 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); -- 2.1.1