From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934327Ab2GLXDM (ORCPT ); Thu, 12 Jul 2012 19:03:12 -0400 Received: from mail-gg0-f174.google.com ([209.85.161.174]:52623 "EHLO mail-gg0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162475Ab2GLXC4 (ORCPT ); Thu, 12 Jul 2012 19:02:56 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Russell King , UCHINO Satoshi Subject: [ 04/68] ARM: fix rcu stalls on SMP platforms Date: Thu, 12 Jul 2012 16:01:38 -0700 Message-Id: <20120712175035.807940289@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712175035.530652872@linuxfoundation.org> References: <20120712175057.GA9917@kroah.com> <20120712175035.530652872@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Russell King commit 7deabca0acfe02b8e18f59a4c95676012f49a304 upstream. We can stall RCU processing on SMP platforms if a CPU sits in its idle loop for a long time. This happens because we don't call irq_enter() and irq_exit() around generic_smp_call_function_interrupt() and friends. Add the necessary calls, and remove the one from within ipi_timer(), so that they're all in a common place. Signed-off-by: Russell King [add irq_enter()/irq_exit() in do_local_timer] Signed-off-by: UCHINO Satoshi Signed-off-by: Greg Kroah-Hartman --- arch/arm/kernel/smp.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -445,9 +445,7 @@ static DEFINE_PER_CPU(struct clock_event static void ipi_timer(void) { struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent); - irq_enter(); evt->event_handler(evt); - irq_exit(); } #ifdef CONFIG_LOCAL_TIMERS @@ -458,7 +456,9 @@ asmlinkage void __exception_irq_entry do if (local_timer_ack()) { __inc_irq_stat(cpu, local_timer_irqs); + irq_enter(); ipi_timer(); + irq_exit(); } set_irq_regs(old_regs); @@ -568,7 +568,9 @@ asmlinkage void __exception_irq_entry do switch (ipinr) { case IPI_TIMER: + irq_enter(); ipi_timer(); + irq_exit(); break; case IPI_RESCHEDULE: @@ -576,15 +578,21 @@ asmlinkage void __exception_irq_entry do break; case IPI_CALL_FUNC: + irq_enter(); generic_smp_call_function_interrupt(); + irq_exit(); break; case IPI_CALL_FUNC_SINGLE: + irq_enter(); generic_smp_call_function_single_interrupt(); + irq_exit(); break; case IPI_CPU_STOP: + irq_enter(); ipi_cpu_stop(cpu); + irq_exit(); break; default: