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authorThomas Gleixner <tglx@linutronix.de>2011-01-28 08:47:15 +0100
committerThomas Gleixner <tglx@linutronix.de>2011-02-02 22:15:08 +0100
commitf1a06390d013244e721372b3f9b66e39b6429c71 (patch)
tree8ffce4d07e61d3533d17a2b2f947aefcebde211c /kernel
parentafe8a887550f7cc24eb16449670b93f6b43c32d8 (diff)
downloadlinux-linaro-stable-f1a06390d013244e721372b3f9b66e39b6429c71.tar.gz
genirq: Prevent irq storm on migration
move_native_irq() masks and unmasks the interrupt line unconditionally, but the interrupt line might be masked due to a threaded oneshot handler in progress. Unmasking the line in that case can lead to interrupt storms. Observed on PREEMPT_RT. Originally-from: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: stable@kernel.org
Diffstat (limited to 'kernel')
-rw-r--r--kernel/irq/migration.c14
1 files changed, 11 insertions, 3 deletions
diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c
index 1d2541940480..441fd629ff04 100644
--- a/kernel/irq/migration.c
+++ b/kernel/irq/migration.c
@@ -56,6 +56,7 @@ void move_masked_irq(int irq)
void move_native_irq(int irq)
{
struct irq_desc *desc = irq_to_desc(irq);
+ bool masked;
if (likely(!(desc->status & IRQ_MOVE_PENDING)))
return;
@@ -63,8 +64,15 @@ void move_native_irq(int irq)
if (unlikely(desc->status & IRQ_DISABLED))
return;
- desc->irq_data.chip->irq_mask(&desc->irq_data);
+ /*
+ * Be careful vs. already masked interrupts. If this is a
+ * threaded interrupt with ONESHOT set, we can end up with an
+ * interrupt storm.
+ */
+ masked = desc->status & IRQ_MASKED;
+ if (!masked)
+ desc->irq_data.chip->irq_mask(&desc->irq_data);
move_masked_irq(irq);
- desc->irq_data.chip->irq_unmask(&desc->irq_data);
+ if (!masked)
+ desc->irq_data.chip->irq_unmask(&desc->irq_data);
}
-