From a77353e5eb56b6c6098bfce59aff1f449451b0b7 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Wed, 25 Jun 2014 07:13:07 +0200 Subject: [PATCH] irq_work: Remove BUG_ON in irq_work_run() Because of a collision with 8d056c48e486 ("CPU hotplug, smp: flush any pending IPI callbacks before CPU offline"), which ends up calling hotplug_cfd()->flush_smp_call_function_queue()->irq_work_run(), which is not from IRQ context. And since that already calls irq_work_run() from the hotplug path, remove our entire hotplug handling. Reported-by: Stephen Warren Tested-by: Stephen Warren Reviewed-by: Srivatsa S. Bhat Cc: Frederic Weisbecker Cc: Linus Torvalds Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/n/tip-busatzs2gvz4v62258agipuf@git.kernel.org Signed-off-by: Ingo Molnar --- kernel/irq_work.c | 46 ++++------------------------------------------ 1 file changed, 4 insertions(+), 42 deletions(-) diff --git a/kernel/irq_work.c b/kernel/irq_work.c index 4b0a890a304a..e6bcbe756663 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -160,20 +160,14 @@ static void irq_work_run_list(struct llist_head *list) } } -static void __irq_work_run(void) -{ - irq_work_run_list(&__get_cpu_var(raised_list)); - irq_work_run_list(&__get_cpu_var(lazy_list)); -} - /* - * Run the irq_work entries on this cpu. Requires to be ran from hardirq - * context with local IRQs disabled. + * hotplug calls this through: + * hotplug_cfd() -> flush_smp_call_function_queue() */ void irq_work_run(void) { - BUG_ON(!in_irq()); - __irq_work_run(); + irq_work_run_list(&__get_cpu_var(raised_list)); + irq_work_run_list(&__get_cpu_var(lazy_list)); } EXPORT_SYMBOL_GPL(irq_work_run); @@ -189,35 +183,3 @@ void irq_work_sync(struct irq_work *work) cpu_relax(); } EXPORT_SYMBOL_GPL(irq_work_sync); - -#ifdef CONFIG_HOTPLUG_CPU -static int irq_work_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - long cpu = (long)hcpu; - - switch (action) { - case CPU_DYING: - /* Called from stop_machine */ - if (WARN_ON_ONCE(cpu != smp_processor_id())) - break; - __irq_work_run(); - break; - default: - break; - } - return NOTIFY_OK; -} - -static struct notifier_block cpu_notify; - -static __init int irq_work_init_cpu_notifier(void) -{ - cpu_notify.notifier_call = irq_work_cpu_notify; - cpu_notify.priority = 0; - register_cpu_notifier(&cpu_notify); - return 0; -} -device_initcall(irq_work_init_cpu_notifier); - -#endif /* CONFIG_HOTPLUG_CPU */ -- 2.30.2