3.14.61-rt63-rc1 stable review patch. If anyone has any objections, please let me know.
------------------ From: Thomas Gleixner <[email protected]> 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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: [email protected] Signed-off-by: Steven Rostedt <[email protected]> --- include/linux/irq_work.h | 6 ++++++ kernel/irq_work.c | 9 +++++++++ kernel/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 4a8c7a2df480..ccd736ebee9e 100644 --- a/include/linux/irq_work.h +++ b/include/linux/irq_work.h @@ -44,4 +44,10 @@ 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 af8ceafc94e4..883bb73698b9 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -163,8 +163,17 @@ 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/timer.c b/kernel/timer.c index 300870358b4f..3796af212c95 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1450,7 +1450,7 @@ void update_process_times(int user_tick) scheduler_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_run(); #endif @@ -1466,9 +1466,7 @@ 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
