From patchwork Thu Jul 23 02:00:09 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kamal Mostafa X-Patchwork-Id: 6849181 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork1.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork1.web.kernel.org (Postfix) with ESMTP id CF5E49F380 for ; Thu, 23 Jul 2015 02:05:24 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id 5D2B6206D4 for ; Thu, 23 Jul 2015 02:05:23 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.9]) (using TLSv1.2 with cipher AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4F8E6206B2 for ; Thu, 23 Jul 2015 02:05:22 +0000 (UTC) Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZI5qB-0006Cb-2q; Thu, 23 Jul 2015 02:02:31 +0000 Received: from youngberry.canonical.com ([91.189.89.112]) by bombadil.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1ZI5q8-00068q-01 for linux-arm-kernel@lists.infradead.org; Thu, 23 Jul 2015 02:02:28 +0000 Received: from 1.general.kamal.us.vpn ([10.172.68.52] helo=fourier) by youngberry.canonical.com with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:16) (Exim 4.76) (envelope-from ) id 1ZI5pj-0005jl-7T; Thu, 23 Jul 2015 02:02:03 +0000 Received: from kamal by fourier with local (Exim 4.82) (envelope-from ) id 1ZI5ph-0006DL-01; Wed, 22 Jul 2015 19:02:01 -0700 From: Kamal Mostafa To: linux-kernel@vger.kernel.org, stable@vger.kernel.org, kernel-team@lists.ubuntu.com Subject: [PATCH 3.13.y-ckt 091/132] clocksource: exynos_mct: Avoid blocking calls in the cpu hotplug notifier Date: Wed, 22 Jul 2015 19:00:09 -0700 Message-Id: <1437616850-23266-92-git-send-email-kamal@canonical.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1437616850-23266-1-git-send-email-kamal@canonical.com> References: <1437616850-23266-1-git-send-email-kamal@canonical.com> X-Extended-Stable: 3.13 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20150722_190228_215307_4F5EB107 X-CRM114-Status: GOOD ( 17.31 ) X-Spam-Score: -5.4 (-----) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kamal Mostafa , daniel.lezcano@linaro.org, kyungmin.park@samsung.com, Damian Eppel , kgene@kernel.org, Thomas Gleixner , linux-arm-kernel@lists.infradead.org, m.szyprowski@samsung.com MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Spam-Status: No, score=-5.4 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_MED, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP 3.13.11-ckt24 -stable review patch. If anyone has any objections, please let me know. ------------------ From: Damian Eppel commit 56a94f13919c0db5958611b388e1581b4852f3c9 upstream. Whilst testing cpu hotplug events on kernel configured with DEBUG_PREEMPT and DEBUG_ATOMIC_SLEEP we get following BUG message, caused by calling request_irq() and free_irq() in the context of hotplug notification (which is in this case atomic context). [ 40.785859] CPU1: Software reset [ 40.786660] BUG: sleeping function called from invalid context at mm/slub.c:1241 [ 40.786668] in_atomic(): 1, irqs_disabled(): 128, pid: 0, name: swapper/1 [ 40.786678] Preemption disabled at:[< (null)>] (null) [ 40.786681] [ 40.786692] CPU: 1 PID: 0 Comm: swapper/1 Not tainted 3.19.0-rc4-00024-g7dca860 #36 [ 40.786698] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree) [ 40.786728] [] (unwind_backtrace) from [] (show_stack+0x10/0x14) [ 40.786747] [] (show_stack) from [] (dump_stack+0x70/0xbc) [ 40.786767] [] (dump_stack) from [] (kmem_cache_alloc+0xd8/0x170) [ 40.786785] [] (kmem_cache_alloc) from [] (request_threaded_irq+0x64/0x128) [ 40.786804] [] (request_threaded_irq) from [] (exynos4_local_timer_setup+0xc0/0x13c) [ 40.786820] [] (exynos4_local_timer_setup) from [] (exynos4_mct_cpu_notify+0x30/0xa8) [ 40.786838] [] (exynos4_mct_cpu_notify) from [] (notifier_call_chain+0x44/0x84) [ 40.786857] [] (notifier_call_chain) from [] (__cpu_notify+0x28/0x44) [ 40.786873] [] (__cpu_notify) from [] (secondary_start_kernel+0xec/0x150) [ 40.786886] [] (secondary_start_kernel) from [<40008764>] (0x40008764) Interrupts cannot be requested/freed in the CPU_STARTING/CPU_DYING notifications which run on the hotplugged cpu with interrupts and preemption disabled. To avoid the issue, request the interrupts for all possible cpus in the boot code. The interrupts are marked NO_AUTOENABLE to avoid a racy request_irq/disable_irq() sequence. The flag prevents the request_irq() code from enabling the interrupt immediately. The interrupt is then enabled in the CPU_STARTING notifier of the hotplugged cpu and again disabled with disable_irq_nosync() in the CPU_DYING notifier. [ tglx: Massaged changelog to match the patch ] Fixes: 7114cd749a12 ("clocksource: exynos_mct: use (request/free)_irq calls for local timer registration") Reported-by: Krzysztof Kozlowski Reviewed-by: Krzysztof Kozlowski Tested-by: Krzysztof Kozlowski Tested-by: Marcin Jabrzyk Signed-off-by: Damian Eppel Cc: m.szyprowski@samsung.com Cc: kyungmin.park@samsung.com Cc: daniel.lezcano@linaro.org Cc: kgene@kernel.org Cc: linux-arm-kernel@lists.infradead.org Link: http://lkml.kernel.org/r/1435324984-7328-1-git-send-email-d.eppel@samsung.com Signed-off-by: Thomas Gleixner Signed-off-by: Kamal Mostafa --- drivers/clocksource/exynos_mct.c | 43 ++++++++++++++++++++++++++++------------ 1 file changed, 30 insertions(+), 13 deletions(-) diff --git a/drivers/clocksource/exynos_mct.c b/drivers/clocksource/exynos_mct.c index 12fbec7..fc0e502 100644 --- a/drivers/clocksource/exynos_mct.c +++ b/drivers/clocksource/exynos_mct.c @@ -418,15 +418,12 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt) exynos4_mct_write(TICK_BASE_CNT, mevt->base + MCT_L_TCNTB_OFFSET); if (mct_int_type == MCT_INT_SPI) { - evt->irq = mct_irqs[MCT_L0_IRQ + cpu]; - if (request_irq(evt->irq, exynos4_mct_tick_isr, - IRQF_TIMER | IRQF_NOBALANCING, - evt->name, mevt)) { - pr_err("exynos-mct: cannot register IRQ %d\n", - evt->irq); + + if (evt->irq == -1) return -EIO; - } - irq_force_affinity(mct_irqs[MCT_L0_IRQ + cpu], cpumask_of(cpu)); + + irq_force_affinity(evt->irq, cpumask_of(cpu)); + enable_irq(evt->irq); } else { enable_percpu_irq(mct_irqs[MCT_L0_IRQ], 0); } @@ -439,10 +436,12 @@ static int exynos4_local_timer_setup(struct clock_event_device *evt) static void exynos4_local_timer_stop(struct clock_event_device *evt) { evt->set_mode(CLOCK_EVT_MODE_UNUSED, evt); - if (mct_int_type == MCT_INT_SPI) - free_irq(evt->irq, this_cpu_ptr(&percpu_mct_tick)); - else + if (mct_int_type == MCT_INT_SPI) { + if (evt->irq != -1) + disable_irq_nosync(evt->irq); + } else { disable_percpu_irq(mct_irqs[MCT_L0_IRQ]); + } } static int exynos4_mct_cpu_notify(struct notifier_block *self, @@ -474,7 +473,7 @@ static struct notifier_block exynos4_mct_cpu_nb = { static void __init exynos4_timer_resources(struct device_node *np, void __iomem *base) { - int err; + int err, cpu; struct mct_clock_event_device *mevt = this_cpu_ptr(&percpu_mct_tick); struct clk *mct_clk, *tick_clk; @@ -501,7 +500,25 @@ static void __init exynos4_timer_resources(struct device_node *np, void __iomem WARN(err, "MCT: can't request IRQ %d (%d)\n", mct_irqs[MCT_L0_IRQ], err); } else { - irq_set_affinity(mct_irqs[MCT_L0_IRQ], cpumask_of(0)); + for_each_possible_cpu(cpu) { + int mct_irq = mct_irqs[MCT_L0_IRQ + cpu]; + struct mct_clock_event_device *pcpu_mevt = + per_cpu_ptr(&percpu_mct_tick, cpu); + + pcpu_mevt->evt.irq = -1; + + irq_set_status_flags(mct_irq, IRQ_NOAUTOEN); + if (request_irq(mct_irq, + exynos4_mct_tick_isr, + IRQF_TIMER | IRQF_NOBALANCING, + pcpu_mevt->name, pcpu_mevt)) { + pr_err("exynos-mct: cannot register IRQ (cpu%d)\n", + cpu); + + continue; + } + pcpu_mevt->evt.irq = mct_irq; + } } err = register_cpu_notifier(&exynos4_mct_cpu_nb);