diff --git a/runtime/src/local_runqueue_minheap.c b/runtime/src/local_runqueue_minheap.c
index 10b0bc6..045bb3f 100644
--- a/runtime/src/local_runqueue_minheap.c
+++ b/runtime/src/local_runqueue_minheap.c
@@ -119,8 +119,10 @@ err:
 void
 local_runqueue_minheap_preempt(ucontext_t *user_context)
 {
-	/* Assumption: Software Interrupts are disabed by caller */
-	assert(!software_interrupt_is_enabled());
+	assert(user_context != NULL);
+
+	/* Prevent nested preemption */
+	software_interrupt_disable();
 
 	struct sandbox *current_sandbox = current_sandbox_get();
 
diff --git a/runtime/src/software_interrupt.c b/runtime/src/software_interrupt.c
index 01baabf..fc4c249 100644
--- a/runtime/src/software_interrupt.c
+++ b/runtime/src/software_interrupt.c
@@ -111,7 +111,6 @@ software_interrupt_handle_signals(int signal_type, siginfo_t *signal_info, void
 		if (current_sandbox->state == SANDBOX_RETURNED) return;
 
 		/* Preempt */
-		software_interrupt_disable();
 		local_runqueue_preempt(user_context);
 
 		return;