diff --git a/mysql-test/suite/parts/r/mdev_40995.result b/mysql-test/suite/parts/r/mdev_40995.result
new file mode 100644
index 0000000000000..f187b37412ddf
--- /dev/null
+++ b/mysql-test/suite/parts/r/mdev_40995.result
@@ -0,0 +1,28 @@
+#
+# MDEV-40995 concurrent INSERT ... SELECT on a partitioned InnoDB table
+# can leave the table-level AUTO_INCREMENT counter behind MAX(pk)
+#
+CREATE TABLE t1 (
+id INT AUTO_INCREMENT,
+pk2 INT NOT NULL,
+a INT,
+PRIMARY KEY (id, pk2),
+UNIQUE KEY (a, pk2)
+) ENGINE=InnoDB PARTITION BY HASH(pk2) PARTITIONS 2;
+INSERT INTO t1 (pk2, a) VALUES (1, 10), (1, 100), (1, 110);
+connect  con1,localhost,root,,;
+connect  con2,localhost,root,,;
+connection con1;
+SET DEBUG_SYNC = 'ha_partition_get_auto_increment_after_reservation SIGNAL start_t2 WAIT_FOR t2_done EXECUTE 1';
+INSERT INTO t1 (pk2, a) SELECT pk2, a+10 FROM t1 WHERE pk2=1 ORDER BY a;;
+connection con2;
+SET DEBUG_SYNC = 'now WAIT_FOR start_t2';
+INSERT INTO t1 (pk2, a) VALUES (2, 200);
+SET DEBUG_SYNC = 'now SIGNAL t2_done';
+connection con1;
+ERROR 23000: Duplicate entry '110-1' for key 'a'
+connection default;
+INSERT INTO t1 (pk2, a) VALUES (2, 300);
+INSERT INTO t1 (pk2, a) VALUES (2, 400);
+DROP TABLE t1;
+SET DEBUG_SYNC = 'RESET';
diff --git a/mysql-test/suite/parts/t/mdev_40995-master.opt b/mysql-test/suite/parts/t/mdev_40995-master.opt
new file mode 100644
index 0000000000000..571c7877f11a3
--- /dev/null
+++ b/mysql-test/suite/parts/t/mdev_40995-master.opt
@@ -0,0 +1 @@
+--innodb-autoinc-lock-mode=2
diff --git a/mysql-test/suite/parts/t/mdev_40995.test b/mysql-test/suite/parts/t/mdev_40995.test
new file mode 100644
index 0000000000000..d00ad9e032d61
--- /dev/null
+++ b/mysql-test/suite/parts/t/mdev_40995.test
@@ -0,0 +1,41 @@
+--source include/have_debug_sync.inc
+--source include/have_partition.inc
+--source include/have_innodb.inc
+
+--echo #
+--echo # MDEV-40995 concurrent INSERT ... SELECT on a partitioned InnoDB table
+--echo # can leave the table-level AUTO_INCREMENT counter behind MAX(pk)
+--echo #
+
+CREATE TABLE t1 (
+  id INT AUTO_INCREMENT,
+  pk2 INT NOT NULL,
+  a INT,
+  PRIMARY KEY (id, pk2),
+  UNIQUE KEY (a, pk2)
+) ENGINE=InnoDB PARTITION BY HASH(pk2) PARTITIONS 2;
+
+INSERT INTO t1 (pk2, a) VALUES (1, 10), (1, 100), (1, 110);
+
+--connect (con1,localhost,root,,)
+--connect (con2,localhost,root,,)
+
+--connection con1
+SET DEBUG_SYNC = 'ha_partition_get_auto_increment_after_reservation SIGNAL start_t2 WAIT_FOR t2_done EXECUTE 1';
+--send INSERT INTO t1 (pk2, a) SELECT pk2, a+10 FROM t1 WHERE pk2=1 ORDER BY a;
+
+--connection con2
+SET DEBUG_SYNC = 'now WAIT_FOR start_t2';
+INSERT INTO t1 (pk2, a) VALUES (2, 200);
+SET DEBUG_SYNC = 'now SIGNAL t2_done';
+
+--connection con1
+--error ER_DUP_ENTRY
+--reap
+
+--connection default
+INSERT INTO t1 (pk2, a) VALUES (2, 300);
+INSERT INTO t1 (pk2, a) VALUES (2, 400);
+
+DROP TABLE t1;
+SET DEBUG_SYNC = 'RESET';
diff --git a/sql/ha_partition.cc b/sql/ha_partition.cc
index e1e04c359211b..47dcee1eab13b 100644
--- a/sql/ha_partition.cc
+++ b/sql/ha_partition.cc
@@ -11107,6 +11107,7 @@ void ha_partition::get_auto_increment(ulonglong offset, ulonglong increment,
     part_share->next_auto_inc_val+= nb_desired_values * increment;
 
     unlock_auto_increment();
+    DEBUG_SYNC(ha_thd(), "ha_partition_get_auto_increment_after_reservation");
     DBUG_PRINT("info", ("*first_value: %lu", (ulong) *first_value));
     *nb_reserved_values= nb_desired_values;
   }
@@ -11139,7 +11140,8 @@ void ha_partition::release_auto_increment()
         we can lower the reserved value.
       */
       if (next_insert_id < next_auto_inc_val &&
-          auto_inc_interval_for_cur_row.maximum() >= next_auto_inc_val)
+          auto_inc_interval_for_cur_row.maximum() >= next_auto_inc_val &&
+          next_insert_id >= auto_inc_interval_for_cur_row.minimum())
       {
         THD *thd= ha_thd();
         /*