From: Eric W. Biederman Thanks to YH Lu for spotting this. It appears I missed this function when I refactored allocate_irq_vector and introduced irq_domain, with the result that all retriggered irqs would go to cpu 0 even if we were not prepared to receive them there. While reviewing YH's patch I also noticed that this function was missing locking, and since I am now reading two values from two diffrent arrays that looks like a race we might be able to hit in the real world. Cc: Yinghai Lu Signed-off-by: Eric W. Biederman Signed-off-by: Andrew Morton --- arch/x86_64/kernel/io_apic.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff -puN arch/x86_64/kernel/io_apic.c~x86_64-irq-use-irq_domain-in-ioapic_retrigger_irq arch/x86_64/kernel/io_apic.c --- a/arch/x86_64/kernel/io_apic.c~x86_64-irq-use-irq_domain-in-ioapic_retrigger_irq +++ a/arch/x86_64/kernel/io_apic.c @@ -1255,12 +1255,15 @@ static int ioapic_retrigger_irq(unsigned { cpumask_t mask; unsigned vector; + unsigned long flags; + spin_lock_irqsave(&vector_lock, flags); vector = irq_vector[irq]; cpus_clear(mask); - cpu_set(vector >> 8, mask); + cpu_set(first_cpu(irq_domain[irq]), mask); - send_IPI_mask(mask, vector & 0xff); + send_IPI_mask(mask, vector); + spin_unlock_irqrestore(&vector_lock, flags); return 1; } _