From patchwork Fri Jan 27 10:55:19 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jiri Slaby X-Patchwork-Id: 9541469 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 33C9460429 for ; Fri, 27 Jan 2017 11:34:35 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 24E8324560 for ; Fri, 27 Jan 2017 11:34:35 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1992B27F99; Fri, 27 Jan 2017 11:34:35 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0862924560 for ; Fri, 27 Jan 2017 11:34:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934440AbdA0Lec (ORCPT ); Fri, 27 Jan 2017 06:34:32 -0500 Received: from mx2.suse.de ([195.135.220.15]:36793 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933504AbdA0LNJ (ORCPT ); Fri, 27 Jan 2017 06:13:09 -0500 X-Virus-Scanned: by amavisd-new at test-mx.suse.de X-Amavis-Alert: BAD HEADER SECTION, Duplicate header field: "References" Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id E4C98ADFA; Fri, 27 Jan 2017 11:09:34 +0000 (UTC) From: Jiri Slaby To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Joonyoung Shim , linux-samsung-soc@vger.kernel.org, cw00.choi@samsung.com, daniel.lezcano@linaro.org, javier@osg.samsung.com, kgene@kernel.org, krzk@kernel.org, linux-arm-kernel@lists.infradead.org, Thomas Gleixner , Jiri Slaby Subject: [PATCH 3.12 186/235] clocksource/exynos_mct: Clear interrupt when cpu is shut down Date: Fri, 27 Jan 2017 11:55:19 +0100 Message-Id: <0d340098985b2c0f72f12c12106b83fd1079a60f.1485514374.git.jslaby@suse.cz> X-Mailer: git-send-email 2.11.0 In-Reply-To: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> References: <5b46dc789ca2be4046e4e40a131858d386cac741.1485514374.git.jslaby@suse.cz> In-Reply-To: References: Sender: linux-samsung-soc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-samsung-soc@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Joonyoung Shim 3.12-stable review patch. If anyone has any objections, please let me know. =============== 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: Jiri Slaby --- 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 af994880be72..26bfe09ce0fb 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -439,6 +439,7 @@ static void exynos4_local_timer_stop(struct mct_clock_event_device *mevt) 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]); }