Commit 74eed016 authored Feb 20, 2013 by Thomas Gleixner

irq: Ensure irq_exit() code runs with interrupts disabled



We had already a few problems with code called from irq_exit() when
interrupted from a nesting interrupt. This can happen on architectures
which do not define __ARCH_IRQ_EXIT_IRQS_DISABLED.

__ARCH_IRQ_EXIT_IRQS_DISABLED should go away and we want to make it
mandatory to call irq_exit() with interrupts disabled.

As a temporary protection disable interrupts for those architectures
which do not define __ARCH_IRQ_EXIT_IRQS_DISABLED and add a WARN_ONCE
when an architecture which defines __ARCH_IRQ_EXIT_IRQS_DISABLED calls
irq_exit() with interrupts enabled.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linuxfoundation.org>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1302202155320.22263@ionos

parent e5ab012c

kernel/softirq.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -341,6 +341,14 @@ static inline void invoke_softirq(void)
		*/
		void irq_exit(void)
		{
		#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
		unsigned long flags;

		local_irq_save(flags);
		#else
		WARN_ON_ONCE(!irqs_disabled());
		#endif

		account_irq_exit_time(current);
		trace_hardirq_exit();
		sub_preempt_count(IRQ_EXIT_OFFSET);
		@@ -354,6 +362,9 @@ void irq_exit(void)
		#endif
		rcu_irq_exit();
		sched_preempt_enable_no_resched();
		#ifndef __ARCH_IRQ_EXIT_IRQS_DISABLED
		local_irq_restore(flags);
		#endif
		}

		/*

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