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| author | Thomas Gleixner <tglx@linutronix.de> | 2011-01-28 08:47:15 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2011-02-02 22:15:08 +0100 |
| commit | f1a06390d013244e721372b3f9b66e39b6429c71 (patch) | |
| tree | 8ffce4d07e61d3533d17a2b2f947aefcebde211c | |
| parent | afe8a887550f7cc24eb16449670b93f6b43c32d8 (diff) | |
| download | linux-f1a06390d013244e721372b3f9b66e39b6429c71.tar.gz linux-f1a06390d013244e721372b3f9b66e39b6429c71.tar.bz2 linux-f1a06390d013244e721372b3f9b66e39b6429c71.zip | |
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
| -rw-r--r-- | kernel/irq/migration.c | 14 |
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); } - |