From patchwork Fri Mar 10 11:46:23 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ben Hutchings X-Patchwork-Id: 9617247 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 011146046A for ; Fri, 10 Mar 2017 13:49:33 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D554F28710 for ; Fri, 10 Mar 2017 13:49:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C9E5928713; Fri, 10 Mar 2017 13:49:32 +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 4ABF128711 for ; Fri, 10 Mar 2017 13:49:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935181AbdCJNrk (ORCPT ); Fri, 10 Mar 2017 08:47:40 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:43467 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934263AbdCJLwU (ORCPT ); Fri, 10 Mar 2017 06:52:20 -0500 Received: from 82-70-136-246.dsl.in-addr.zen.co.uk ([82.70.136.246] helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1cmJ5g-0008Mu-RS; Fri, 10 Mar 2017 11:52:13 +0000 Received: from ben by deadeye with local (Exim 4.89) (envelope-from ) id 1cmJ5T-0003js-4z; Fri, 10 Mar 2017 11:51:59 +0000 Content-Disposition: inline MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, daniel.lezcano@linaro.org, kgene@kernel.org, "Thomas Gleixner" , "Seung-Woo Kim" , linux-arm-kernel@lists.infradead.org, javier@osg.samsung.com, cw00.choi@samsung.com, krzk@kernel.org, linux-samsung-soc@vger.kernel.org, "Joonyoung Shim" Date: Fri, 10 Mar 2017 11:46:23 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 229/370] clocksource/exynos_mct: Clear interrupt when cpu is shut down In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false 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 3.16.42-rc1 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 [bwh: Backported to 3.16: add definition of the 'mevt' variable, added earlier upstream] Signed-off-by: Ben Hutchings --- -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -458,10 +458,15 @@ static int exynos4_local_timer_setup(str static void exynos4_local_timer_stop(struct clock_event_device *evt) { + struct mct_clock_event_device *mevt; + + mevt = container_of(evt, struct mct_clock_event_device, evt); + evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); 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]); }