From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423250AbcBZVns (ORCPT ); Fri, 26 Feb 2016 16:43:48 -0500 Received: from mail.kernel.org ([198.145.29.136]:48251 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755177AbcBZVdq (ORCPT ); Fri, 26 Feb 2016 16:33:46 -0500 Message-Id: <20160226213341.582113472@goodmis.org> User-Agent: quilt/0.61-1 Date: Fri, 26 Feb 2016 16:32:45 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-rt-users Cc: Thomas Gleixner , Carsten Emde , Sebastian Andrzej Siewior , John Kacur , Paul Gortmaker , Subject: [PATCH RT 10/12] irqwork: Move irq safe work to irq context References: <20160226213235.253312067@goodmis.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Disposition: inline; filename=0010-irqwork-Move-irq-safe-work-to-irq-context.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.18.27-rt26-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Thomas Gleixner On architectures where arch_irq_work_has_interrupt() returns false, we end up running the irq safe work from the softirq context. That results in a potential deadlock in the scheduler irq work which expects that function to be called with interrupts disabled. Split the irq_work_tick() function into a hard and soft variant. Call the hard variant from the tick interrupt and add the soft variant to the timer softirq. Reported-and-tested-by: Yanjiang Jin Signed-off-by: Thomas Gleixner Cc: stable-rt@vger.kernel.org Signed-off-by: Steven Rostedt --- include/linux/irq_work.h | 6 ++++++ kernel/irq_work.c | 9 +++++++++ kernel/time/timer.c | 6 ++---- 3 files changed, 17 insertions(+), 4 deletions(-) diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h index 30ef6c214e6f..af7ed9ad52c3 100644 --- a/include/linux/irq_work.h +++ b/include/linux/irq_work.h @@ -51,4 +51,10 @@ bool irq_work_needs_cpu(void); static inline bool irq_work_needs_cpu(void) { return false; } #endif +#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL) +void irq_work_tick_soft(void); +#else +static inline void irq_work_tick_soft(void) { } +#endif + #endif /* _LINUX_IRQ_WORK_H */ diff --git a/kernel/irq_work.c b/kernel/irq_work.c index 9678fd1382a7..3d5a476b58b9 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -200,8 +200,17 @@ void irq_work_tick(void) if (!llist_empty(raised) && !arch_irq_work_has_interrupt()) irq_work_run_list(raised); + + if (!IS_ENABLED(CONFIG_PREEMPT_RT_FULL)) + irq_work_run_list(this_cpu_ptr(&lazy_list)); +} + +#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL) +void irq_work_tick_soft(void) +{ irq_work_run_list(this_cpu_ptr(&lazy_list)); } +#endif /* * Synchronize against the irq_work @entry, ensures the entry is not diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 3a978d000fce..78e39b644780 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1451,7 +1451,7 @@ void update_process_times(int user_tick) run_local_timers(); rcu_check_callbacks(cpu, user_tick); -#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL) +#if defined(CONFIG_IRQ_WORK) if (in_irq()) irq_work_tick(); #endif @@ -1467,9 +1467,7 @@ static void run_timer_softirq(struct softirq_action *h) hrtimer_run_pending(); -#if defined(CONFIG_IRQ_WORK) && defined(CONFIG_PREEMPT_RT_FULL) - irq_work_tick(); -#endif + irq_work_tick_soft(); if (time_after_eq(jiffies, base->timer_jiffies)) __run_timers(base); -- 2.7.0