diff --git a/mysql-test/main/deadlock_ftwrl.result b/mysql-test/main/deadlock_ftwrl.result
new file mode 100644
index 00000000000..95eed70f664
--- /dev/null
+++ b/mysql-test/main/deadlock_ftwrl.result
@@ -0,0 +1,21 @@
+CREATE TABLE t1(a INT);
+SELECT GET_LOCK("l1", 0);
+GET_LOCK("l1", 0)
+1
+connect con1,localhost,root,,;
+LOCK TABLES t1 WRITE;
+connection default;
+set debug_sync='mdl_acquire_lock_wait SIGNAL ftwrl';
+FLUSH TABLES WITH READ LOCK;
+connection con1;
+set debug_sync='now WAIT_FOR ftwrl';
+SELECT GET_LOCK("l1", 1000);
+ERROR 40001: Deadlock found when trying to get lock; try restarting transaction
+disconnect con1;
+connection default;
+SELECT RELEASE_LOCK("l1");
+RELEASE_LOCK("l1")
+1
+UNLOCK TABLES;
+DROP TABLE t1;
+set debug_sync='reset';
diff --git a/mysql-test/main/deadlock_ftwrl.test b/mysql-test/main/deadlock_ftwrl.test
new file mode 100644
index 00000000000..fc943bcf953
--- /dev/null
+++ b/mysql-test/main/deadlock_ftwrl.test
@@ -0,0 +1,36 @@
+# MDEV-20946 Hard FTWRL deadlock under user level locks
+#
+# Deadlock detector should resolve conflicts between FTWRL and user locks.
+
+--source include/have_debug_sync.inc
+--source include/count_sessions.inc
+
+CREATE TABLE t1(a INT);
+SELECT GET_LOCK("l1", 0);
+
+connect(con1,localhost,root,,);
+LOCK TABLES t1 WRITE;
+
+connection default;
+set debug_sync='mdl_acquire_lock_wait SIGNAL ftwrl';
+send FLUSH TABLES WITH READ LOCK;
+# At this point "default" is waiting for tables to be unlocked from
+# LOCK TABLES WRITE issued by "con1".
+
+connection con1;
+set debug_sync='now WAIT_FOR ftwrl';
+# The lock in the following GET_LOCK cannot be acquired since "default" holds
+# a lock on "l1" and is waiting in FLUSH TABLES for con1.
+--error ER_LOCK_DEADLOCK
+SELECT GET_LOCK("l1", 1000);
+disconnect con1;  # Performs an implicit UNLOCK TABLES.
+
+connection default;
+reap;
+SELECT RELEASE_LOCK("l1");
+UNLOCK TABLES;
+DROP TABLE t1;
+
+set debug_sync='reset';
+
+--source include/wait_until_count_sessions.inc
diff --git a/sql/mdl.cc b/sql/mdl.cc
index 1798d3039fa..5e54178db70 100644
--- a/sql/mdl.cc
+++ b/sql/mdl.cc
@@ -2782,6 +2782,7 @@ void MDL_context::find_deadlock()
       context was waiting is concurrently satisfied.
     */
     (void) victim->m_wait.set_status(MDL_wait::VICTIM);
+    victim->inc_deadlock_overweight();
     victim->unlock_deadlock_victim();
 
     if (victim == this)
diff --git a/sql/mdl.h b/sql/mdl.h
index 9a788b0ea31..a2cb7c2aa85 100644
--- a/sql/mdl.h
+++ b/sql/mdl.h
@@ -909,7 +909,8 @@ public:
 
   /** @pre Only valid if we started waiting for lock. */
   inline uint get_deadlock_weight() const
-  { return m_waiting_for->get_deadlock_weight(); }
+  { return m_waiting_for->get_deadlock_weight() + m_deadlock_overweight; }
+  void inc_deadlock_overweight() { m_deadlock_overweight++; }
   /**
     Post signal to the context (and wake it up if necessary).
 
@@ -1027,6 +1028,7 @@ private:
    */
   MDL_wait_for_subgraph *m_waiting_for;
   LF_PINS *m_pins;
+  uint m_deadlock_overweight= 0;
 private:
   MDL_ticket *find_ticket(MDL_request *mdl_req,
                           enum_mdl_duration *duration);