diff --git a/cmdline/io.c b/cmdline/io.c
index a5e92d93..6c7a7c6e 100644
--- a/cmdline/io.c
+++ b/cmdline/io.c
@@ -751,7 +751,12 @@ static void* io_reader_thread(void* arg)
 		if (task->state == TASK_STATE_EMPTY)
 			continue;
 
-		assert(task->state == TASK_STATE_READY);
+		if (task->state != TASK_STATE_READY) {
+			/* LCOV_EXCL_START */
+			log_fatal(EINTERNAL, "Internal inconsistency: Unexpected state %d in reader for task at position %u in worker %u\n", task->state, task->position, worker->index);
+			os_abort();
+			/* LCOV_EXCL_STOP */
+		}
 
 		/* work on the assigned task */
 		io_reader_worker(worker, task);
@@ -781,7 +786,12 @@ static void* io_writer_thread(void* arg)
 			continue;
 		}
 
-		assert(task->state == TASK_STATE_READY);
+		if (task->state != TASK_STATE_READY) {
+			/* LCOV_EXCL_START */
+			log_fatal(EINTERNAL, "Internal inconsistency: Unexpected state %d in writer for task at position %u in worker %u\n", task->state, task->position, worker->index);
+			os_abort();
+			/* LCOV_EXCL_STOP */
+		}
 
 		/* work on the assigned task */
 		worker->func(worker, task);