diff --git a/arch/arm/kernel/entry-armv.S b/arch/arm/kernel/entry-armv.S
index 77b047475539b9683ef9671caf738adf8ad22a9a..85040cfeb5e515d303afaa7e6025b16e604cda84 100644
--- a/arch/arm/kernel/entry-armv.S
+++ b/arch/arm/kernel/entry-armv.S
@@ -650,6 +650,7 @@ ENTRY(fp_enter)
 no_fp:	mov	pc, lr
 
 __und_usr_unknown:
+	enable_irq
 	mov	r0, sp
 	adr	lr, ret_from_exception
 	b	do_undefinstr