| From 708edcc15e55003da67d61157a905b9373f0772c Mon Sep 17 00:00:00 2001 |
| From: Ingo Molnar <mingo@elte.hu> |
| Date: Fri, 3 Jul 2009 08:29:27 -0500 |
| Subject: [PATCH] genirq: prevent interrupt storm on irq migration |
| |
| commit b87daa2884f9b0196621013731b2be2f736c962e in tip. |
| |
| Migration maks/unmaks interrupts unconditionally. With forced irq |
| threading thats going to result in an interrupt storm when the |
| threaded handler has not finished yet. |
| |
| Signed-off-by: Ingo Molnar <mingo@elte.hu> |
| |
| diff --git a/kernel/irq/migration.c b/kernel/irq/migration.c |
| index 2419622..4817563 100644 |
| --- a/kernel/irq/migration.c |
| +++ b/kernel/irq/migration.c |
| @@ -54,6 +54,7 @@ void move_masked_irq(int irq) |
| void move_native_irq(int irq) |
| { |
| struct irq_desc *desc = irq_to_desc(irq); |
| + int mask = 1; |
| |
| if (likely(!(desc->status & IRQ_MOVE_PENDING))) |
| return; |
| @@ -61,8 +62,17 @@ void move_native_irq(int irq) |
| if (unlikely(desc->status & IRQ_DISABLED)) |
| return; |
| |
| - desc->chip->mask(irq); |
| + /* |
| + * If the irq is already in progress, it should be masked. |
| + * If we unmask it, we might cause an interrupt storm on RT. |
| + */ |
| + if (unlikely(desc->status & IRQ_INPROGRESS)) |
| + mask = 0; |
| + |
| + if (mask) |
| + desc->chip->mask(irq); |
| move_masked_irq(irq); |
| - desc->chip->unmask(irq); |
| + if (mask) |
| + desc->chip->unmask(irq); |
| } |
| |
| -- |
| 1.7.1.1 |
| |
