diff --git a/ChangeLog b/ChangeLog
index 73651f5..2895f53 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -4,6 +4,8 @@
 	the condition inside.
 	(chx_timer_expired, chx_handle_intr): Call unconditionally.
 	(intr_lock): New variable.
+	(chx_handle_intr, chopstx_claim_irq, chopstx_release_irq)
+	(chopstx_release_irq_thread): Add spin lock with intr_lock.
 
 	* chopstx.h (chx_intr): Remove member LOCK.
 
diff --git a/chopstx.c b/chopstx.c
index 2df444a..914b372 100644
--- a/chopstx.c
+++ b/chopstx.c
@@ -1331,6 +1331,7 @@ chopstx_release_irq_thread (struct chx_thread *tp)
   chopstx_intr_t *intr, *intr_prev;
 
   chx_cpu_sched_lock ();
+  chx_spin_lock (&intr_lock);
   intr_prev = intr_top;
   for (intr = intr_top; intr; intr = intr->next)
     if (intr->tp == tp)
@@ -1344,6 +1345,7 @@ chopstx_release_irq_thread (struct chx_thread *tp)
       else
 	intr_prev->next = intr->next;
     }
+  chx_spin_unlock (&intr_lock);
   chx_cpu_sched_unlock ();
 }