The [user space] interface does not filter out offline cpus. It merily guarantees that the mask contains at least one online cpu. So the selector in the irq chip implementation needs to make sure to pick only an online cpu because otherwise: Offline Core 1 Set affinity to 0xe (is valid due to online mask 0xd) cpumask_first will pick core 1, which is offline Signed-off-by: Thomas Gleixner Cc: Tony Luck Cc: Fenghua Yu Cc: ia64 --- arch/ia64/kernel/msi_ia64.c | 5 +---- arch/ia64/sn/kernel/irq.c | 4 ++-- arch/ia64/sn/kernel/msi_sn.c | 2 +- 3 files changed, 4 insertions(+), 7 deletions(-) Index: tip/arch/ia64/kernel/msi_ia64.c =================================================================== --- tip.orig/arch/ia64/kernel/msi_ia64.c +++ tip/arch/ia64/kernel/msi_ia64.c @@ -17,12 +17,9 @@ static int ia64_set_msi_irq_affinity(str { struct msi_msg msg; u32 addr, data; - int cpu = first_cpu(*cpu_mask); + int cpu = cpumask_first_and(cpu_mask, cpu_online_mask); unsigned int irq = idata->irq; - if (!cpu_online(cpu)) - return -1; - if (irq_prepare_move(irq, cpu)) return -1; Index: tip/arch/ia64/sn/kernel/irq.c =================================================================== --- tip.orig/arch/ia64/sn/kernel/irq.c +++ tip/arch/ia64/sn/kernel/irq.c @@ -209,8 +209,8 @@ static int sn_set_affinity_irq(struct ir nasid_t nasid; int slice; - nasid = cpuid_to_nasid(cpumask_first(mask)); - slice = cpuid_to_slice(cpumask_first(mask)); + nasid = cpuid_to_nasid(cpumask_first_and(mask, cpu_online_mask)); + slice = cpuid_to_slice(cpumask_first_and(mask, cpu_online_mask)); list_for_each_entry_safe(sn_irq_info, sn_irq_info_safe, sn_irq_lh[irq], list) Index: tip/arch/ia64/sn/kernel/msi_sn.c =================================================================== --- tip.orig/arch/ia64/sn/kernel/msi_sn.c +++ tip/arch/ia64/sn/kernel/msi_sn.c @@ -166,7 +166,7 @@ static int sn_set_msi_irq_affinity(struc struct sn_pcibus_provider *provider; unsigned int cpu, irq = data->irq; - cpu = cpumask_first(cpu_mask); + cpu = cpumask_first_and(cpu_mask, cpu_online_mask); sn_irq_info = sn_msi_info[irq].sn_irq_info; if (sn_irq_info == NULL || sn_irq_info->irq_int_bit >= 0) return -1; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/