[tip:irq/urgent] irq: Ensure irq_exit() code runs with interrupts disabled

From: tip-bot for Thomas Gleixner
Date: Thu Feb 21 2013 - 15:07:24 EST

Commit-ID: 74eed0163d0def3fce27228d9ccf3d36e207b286
Gitweb: http://git.kernel.org/tip/74eed0163d0def3fce27228d9ccf3d36e207b286
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Wed, 20 Feb 2013 22:00:48 +0100
Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
CommitDate: Thu, 21 Feb 2013 20:52:24 +0100

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@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxx>
Link: alpine.LFD.2.02.1302202155320.22263@ionos">http://lkml.kernel.org/r/alpine.LFD.2.02.1302202155320.22263@ionos

kernel/softirq.c | 11 +++++++++++
1 file changed, 11 insertions(+)

diff --git a/kernel/softirq.c b/kernel/softirq.c
index f5cc25f..f2a9346 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -341,6 +341,14 @@ static inline void invoke_softirq(void)
void irq_exit(void)
+ unsigned long flags;
+ local_irq_save(flags);
+ WARN_ON_ONCE(!irqs_disabled());
@@ -354,6 +362,9 @@ void irq_exit(void)
+ local_irq_restore(flags);

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