diff --git a/criu/include/pstree.h b/criu/include/pstree.h
index 55615fffc..880c926ad 100644
--- a/criu/include/pstree.h
+++ b/criu/include/pstree.h
@@ -2,6 +2,7 @@
 #define __CR_PSTREE_H__
 
 #include "common/list.h"
+#include "common/lock.h"
 #include "pid.h"
 #include "images/core.pb-c.h"
 
@@ -24,8 +25,14 @@ struct pstree_item {
 	struct pid		*threads;	/* array of threads */
 	CoreEntry		**core;
 	TaskKobjIdsEntry	*ids;
+	futex_t			task_st;
 };
 
+enum {
+	FDS_EVENT_BIT	= 0,
+};
+#define FDS_EVENT (1 << FDS_EVENT_BIT)
+
 struct pstree_item *current;
 
 struct rst_info;
diff --git a/criu/pstree.c b/criu/pstree.c
index 7d57d09ab..4711ff948 100644
--- a/criu/pstree.c
+++ b/criu/pstree.c
@@ -219,6 +219,7 @@ struct pstree_item *__alloc_pstree_item(bool rst)
 	item->pid->real = -1;
 	item->born_sid = -1;
 	item->pid->item = item;
+	futex_init(&item->task_st);
 
 	return item;
 }