commit: f1a06390d013244e721372b3f9b66e39b6429c71 From: Thomas Gleixner <[email protected]> Date: Fri, 28 Jan 2011 08:47:15 +0100 Subject: [PATCH] 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 <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Cc: [email protected] --- 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 1d25419..441fd62 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); } - _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
