diff --git a/contrib/intarray/_int_bool.c b/contrib/intarray/_int_bool.c
index c3c39d194b..5d9e676660 100644
--- a/contrib/intarray/_int_bool.c
+++ b/contrib/intarray/_int_bool.c
@@ -564,6 +564,9 @@ typedef struct
 static void
 infix(INFIX *in, bool first)
 {
+	/* since this function recurses, it could be driven to stack overflow. */
+	check_stack_depth();
+
 	if (in->curpol->type == VAL)
 	{
 		RESIZEBUF(in, 11);
diff --git a/contrib/ltree/ltxtquery_io.c b/contrib/ltree/ltxtquery_io.c
index ddc63d7b66..74010f3cef 100644
--- a/contrib/ltree/ltxtquery_io.c
+++ b/contrib/ltree/ltxtquery_io.c
@@ -416,6 +416,9 @@ while( ( (inf)->cur - (inf)->buf ) + (addsize) + 1 >= (inf)->buflen ) \
 static void
 infix(INFIX *in, bool first)
 {
+	/* since this function recurses, it could be driven to stack overflow. */
+	check_stack_depth();
+
 	if (in->curpol->type == VAL)
 	{
 		char	   *op = in->op + in->curpol->distance;
diff --git a/contrib/ltree/ltxtquery_op.c b/contrib/ltree/ltxtquery_op.c
index 64f9d219f7..1428c8b478 100644
--- a/contrib/ltree/ltxtquery_op.c
+++ b/contrib/ltree/ltxtquery_op.c
@@ -8,6 +8,7 @@
 #include <ctype.h>
 
 #include "ltree.h"
+#include "miscadmin.h"
 
 PG_FUNCTION_INFO_V1(ltxtq_exec);
 PG_FUNCTION_INFO_V1(ltxtq_rexec);
@@ -18,6 +19,9 @@ PG_FUNCTION_INFO_V1(ltxtq_rexec);
 bool
 ltree_execute(ITEM *curitem, void *checkval, bool calcnot, bool (*chkcond) (void *checkval, ITEM *val))
 {
+	/* since this function recurses, it could be driven to stack overflow */
+	check_stack_depth();
+
 	if (curitem->type == VAL)
 		return (*chkcond) (checkval, curitem);
 	else if (curitem->val == (int32) '!')
diff --git a/src/backend/utils/adt/tsquery_cleanup.c b/src/backend/utils/adt/tsquery_cleanup.c
index 2545f4eea7..b841006dd0 100644
--- a/src/backend/utils/adt/tsquery_cleanup.c
+++ b/src/backend/utils/adt/tsquery_cleanup.c
@@ -33,6 +33,9 @@ maketree(QueryItem *in)
 {
 	NODE	   *node = (NODE *) palloc(sizeof(NODE));
 
+	/* since this function recurses, it could be driven to stack overflow. */
+	check_stack_depth();
+
 	node->valnode = in;
 	node->right = node->left = NULL;
 	if (in->type == QI_OPR)