Index: mysql-test/innodb-semi-consistent.result
===================================================================
--- mysql-test/innodb-semi-consistent.result	(revision 4398)
+++ mysql-test/innodb-semi-consistent.result	(revision 4399)
@@ -38,3 +38,10 @@
 11
 7
 drop table t1;
+create table t1 (a int, b int) engine=myisam;
+create table t2 (c int, d int, key (c)) engine=innodb;
+insert into t1 values (1,1);
+insert into t2 values (1,2);
+set session transaction isolation level read committed;
+delete from t1 using t1 join t2 on t1.a = t2.c where t2.d in (1);
+drop table t1, t2;
Index: mysql-test/innodb-semi-consistent.test
===================================================================
--- mysql-test/innodb-semi-consistent.test	(revision 4398)
+++ mysql-test/innodb-semi-consistent.test	(revision 4399)
@@ -53,3 +53,16 @@
 connection default;
 disconnect a;
 disconnect b;
+
+# Bug 39320
+create table t1 (a int, b int) engine=myisam;
+create table t2 (c int, d int, key (c)) engine=innodb;
+insert into t1 values (1,1);
+insert into t2 values (1,2);
+connect (a,localhost,root,,);
+connection a;
+set session transaction isolation level read committed;
+delete from t1 using t1 join t2 on t1.a = t2.c where t2.d in (1);
+connection default;
+disconnect a;
+drop table t1, t2;
Index: row/row0sel.c
===================================================================
--- row/row0sel.c	(revision 4398)
+++ row/row0sel.c	(revision 4399)
@@ -2901,8 +2901,9 @@
 func_exit:
 	*out_rec = clust_rec;
 
-	if (prebuilt->select_lock_type == LOCK_X) {
-		/* We may use the cursor in update: store its position */
+	if (prebuilt->select_lock_type != LOCK_NONE) {
+		/* We may use the cursor in update or in unlock_row():
+		store its position */
 
 		btr_pcur_store_position(prebuilt->clust_pcur, mtr);
 	}