diff --git a/arch/powerpc/sysdev/uic.c b/arch/powerpc/sysdev/uic.c
index 22c219e448d4..47180b3fca56 100644
--- a/arch/powerpc/sysdev/uic.c
+++ b/arch/powerpc/sysdev/uic.c
@@ -266,6 +266,9 @@ irqreturn_t uic_cascade(int virq, void *data)
 	int subvirq;
 
 	msr = mfdcr(uic->dcrbase + UIC_MSR);
+	if (!msr) /* spurious interrupt */
+		return IRQ_HANDLED;
+
 	src = 32 - ffs(msr);
 
 	subvirq = irq_linear_revmap(uic->irqhost, src);