From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751065AbdAQJNx (ORCPT ); Tue, 17 Jan 2017 04:13:53 -0500 Received: from terminus.zytor.com ([198.137.202.10]:44258 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750870AbdAQJNo (ORCPT ); Tue, 17 Jan 2017 04:13:44 -0500 Date: Tue, 17 Jan 2017 01:13:08 -0800 From: tip-bot for Joonyoung Shim Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, jy0922.shim@samsung.com, tglx@linutronix.de, mingo@kernel.org, sw0312.kim@samsung.com Reply-To: hpa@zytor.com, linux-kernel@vger.kernel.org, mingo@kernel.org, sw0312.kim@samsung.com, jy0922.shim@samsung.com, tglx@linutronix.de In-Reply-To: <1484628876-22065-1-git-send-email-jy0922.shim@samsung.com> References: <1484628876-22065-1-git-send-email-jy0922.shim@samsung.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:timers/urgent] clocksource/exynos_mct: Clear interrupt when cpu is shut down Git-Commit-ID: bc7c36eedb0c7004aa06c2afc3c5385adada8fa3 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: bc7c36eedb0c7004aa06c2afc3c5385adada8fa3 Gitweb: http://git.kernel.org/tip/bc7c36eedb0c7004aa06c2afc3c5385adada8fa3 Author: Joonyoung Shim AuthorDate: Tue, 17 Jan 2017 13:54:36 +0900 Committer: Thomas Gleixner CommitDate: Tue, 17 Jan 2017 10:08:38 +0100 clocksource/exynos_mct: Clear interrupt when cpu is shut down When a CPU goes offline a potentially pending timer interrupt is not cleared. When the CPU comes online again then the pending interrupt is delivered before the per cpu clockevent device is initialized. As a consequence the tick interrupt handler dereferences a NULL pointer. [ 51.251378] Unable to handle kernel NULL pointer dereference at virtual address 00000040 [ 51.289348] task: ee942d00 task.stack: ee960000 [ 51.293861] PC is at tick_periodic+0x38/0xb0 [ 51.298102] LR is at tick_handle_periodic+0x1c/0x90 Clear the pending interrupt in the cpu dying path. Fixes: 56a94f13919c ("clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier") Reported-by: Seung-Woo Kim Signed-off-by: Joonyoung Shim Cc: linux-samsung-soc@vger.kernel.org Cc: cw00.choi@samsung.com Cc: daniel.lezcano@linaro.org Cc: stable@vger.kernel.org Cc: javier@osg.samsung.com Cc: kgene@kernel.org Cc: krzk@kernel.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1484628876-22065-1-git-send-email-jy0922.shim@samsung.com Signed-off-by: Thomas Gleixner --- drivers/clocksource/exynos_mct.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index 4da1dc2..670ff0f 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -495,6 +495,7 @@ static int exynos4_mct_dying_cpu(unsigned int cpu) if (mct_int_type == MCT_INT_SPI) { if (evt->irq != -1) disable_irq_nosync(evt->irq); + exynos4_mct_write(0x1, mevt->base + MCT_L_INT_CSTAT_OFFSET); } else { disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); }