From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754517Ab2GIOiY (ORCPT ); Mon, 9 Jul 2012 10:38:24 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:38267 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754288Ab2GIOiU (ORCPT ); Mon, 9 Jul 2012 10:38:20 -0400 Message-Id: <20120709143120.752484885@decadent.org.uk> User-Agent: quilt/0.60-1 Date: Mon, 09 Jul 2012 15:31:44 +0100 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Russell King Subject: [ 28/48] ARM: fix rcu stalls on SMP platforms In-Reply-To: <20120709143116.348975190@decadent.org.uk> X-SA-Exim-Connect-IP: 2001:470:1f08:1539:21c:bfff:fe03:f805 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-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.2-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 Signed-off-by: Ben Hutchings --- arch/arm/kernel/smp.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 57db122..26cdc49 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -443,9 +443,7 @@ static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent); 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_GENERIC_CLOCKEVENTS_BROADCAST @@ -548,7 +546,9 @@ void handle_IPI(int ipinr, struct pt_regs *regs) switch (ipinr) { case IPI_TIMER: + irq_enter(); ipi_timer(); + irq_exit(); break; case IPI_RESCHEDULE: @@ -556,15 +556,21 @@ void handle_IPI(int ipinr, struct pt_regs *regs) 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: