A user process setting the CPU affinity of an IRQ for a KVM direct-assigned device via /proc/irq/<IRQ#>/smp_affinity can race with the IRQ being released by QEMU, resulting in a NULL iommu pointer dereference in get_irte().
Signed-off-by: Greg Edwards <[email protected]> --- Dropped the Cc: for stable since this likely wouldn't ever be seen in the real world. We saw it on an automated CI stress test. drivers/iommu/intel_irq_remapping.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c index 9b17489..d926676 100644 --- a/drivers/iommu/intel_irq_remapping.c +++ b/drivers/iommu/intel_irq_remapping.c @@ -70,6 +70,11 @@ static int get_irte(int irq, struct irte *entry) raw_spin_lock_irqsave(&irq_2_ir_lock, flags); + if (unlikely(!irq_iommu->iommu)) { + raw_spin_unlock_irqrestore(&irq_2_ir_lock, flags); + return -1; + } + index = irq_iommu->irte_index + irq_iommu->sub_handle; *entry = *(irq_iommu->iommu->ir_table->base + index); -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
