From patchwork Tue Jan 24 07:55:01 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 9534259 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 8A6506042D for ; Tue, 24 Jan 2017 08:01:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7BAF220453 for ; Tue, 24 Jan 2017 08:01:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 701B222701; Tue, 24 Jan 2017 08:01:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-1.9 required=2.0 tests=BAYES_00 autolearn=ham version=3.3.1 Received: from bombadil.infradead.org (bombadil.infradead.org [65.50.211.133]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id F1C9520453 for ; Tue, 24 Jan 2017 08:01:46 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.87 #1 (Red Hat Linux)) id 1cVw2w-0008NT-0P; Tue, 24 Jan 2017 08:01:42 +0000 Received: from mail.linuxfoundation.org ([140.211.169.12]) by bombadil.infradead.org with esmtps (Exim 4.87 #1 (Red Hat Linux)) id 1cVw2W-0008K5-45 for linux-arm-kernel@lists.infradead.org; Tue, 24 Jan 2017 08:01:18 +0000 Received: from localhost (unknown [78.192.101.3]) by mail.linuxfoundation.org (Postfix) with ESMTPSA id 23CF28CC; Tue, 24 Jan 2017 08:00:55 +0000 (UTC) From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Subject: [PATCH 4.9 061/130] clocksource/exynos_mct: Clear interrupt when cpu is shut down Date: Tue, 24 Jan 2017 08:55:01 +0100 Message-Id: <20170124075537.439363186@linuxfoundation.org> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170124075534.905042535@linuxfoundation.org> References: <20170124075534.905042535@linuxfoundation.org> User-Agent: quilt/0.65 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20170124_000116_281328_5F739202 X-CRM114-Status: UNSURE ( 9.84 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-samsung-soc@vger.kernel.org, Joonyoung Shim , javier@osg.samsung.com, Greg Kroah-Hartman , daniel.lezcano@linaro.org, Seung-Woo Kim , stable@vger.kernel.org, cw00.choi@samsung.com, kgene@kernel.org, krzk@kernel.org, Thomas Gleixner , linux-arm-kernel@lists.infradead.org Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joonyoung Shim commit bc7c36eedb0c7004aa06c2afc3c5385adada8fa3 upstream. 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: 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 Signed-off-by: Greg Kroah-Hartman --- drivers/clocksource/exynos_mct.c | 1 + 1 file changed, 1 insertion(+) --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -495,6 +495,7 @@ static int exynos4_mct_dying_cpu(unsigne 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]); }