From 488e7e7d9fe664feaf3819f7e2b4c3b0f7548515 Mon Sep 17 00:00:00 2001 From: Ingo Molnar 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 Signed-off-by: Paul Gortmaker --- kernel/irq/migration.c | 14 ++++++++++++-- 1 files changed, 12 insertions(+), 2 deletions(-) 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); } -- 1.7.0.4