diff --git a/src/util/taler-exchange-secmod-eddsa.c b/src/util/taler-exchange-secmod-eddsa.c
index cd3fc22f1..8f458f5e3 100644
--- a/src/util/taler-exchange-secmod-eddsa.c
+++ b/src/util/taler-exchange-secmod-eddsa.c
@@ -383,6 +383,8 @@ sign_worker (void *cls)
       }
       GNUNET_assert (0 == pthread_mutex_lock (&work_lock));
     }
+    if (! in_shutdown)
+      break;
     /* queue is empty, wait for work */
     GNUNET_assert (0 ==
                    pthread_cond_wait (&work_cond,
diff --git a/src/util/taler-exchange-secmod-rsa.c b/src/util/taler-exchange-secmod-rsa.c
index 41d78bcf3..27d3d7a96 100644
--- a/src/util/taler-exchange-secmod-rsa.c
+++ b/src/util/taler-exchange-secmod-rsa.c
@@ -446,6 +446,8 @@ sign_worker (void *cls)
       }
       GNUNET_assert (0 == pthread_mutex_lock (&work_lock));
     }
+    if (! in_shutdown)
+      break;
     /* queue is empty, wait for work */
     GNUNET_assert (0 ==
                    pthread_cond_wait (&work_cond,