Index: sys/kern/subr_intr.c
===================================================================
--- sys/kern/subr_intr.c
+++ sys/kern/subr_intr.c
@@ -428,10 +428,8 @@
 
 	if (isrc->isrc_irq >= intr_nirq)
 		return (EINVAL);
-	if (irq_sources[isrc->isrc_irq] != isrc)
-		return (EINVAL);
-
-	irq_sources[isrc->isrc_irq] = NULL;
+	if (irq_sources[isrc->isrc_irq] == isrc)
+		irq_sources[isrc->isrc_irq] = NULL;
 	isrc->isrc_irq = INTR_IRQ_INVALID;	/* just to be safe */
 
 	/*