From 81e00485c3eb4be044bbca398f1a4e479ebcc3ac Mon Sep 17 00:00:00 2001
From: Rucha Deodhar <rucha.deodhar@mariadb.com>
Date: Fri, 16 Oct 2020 20:19:09 +0530
Subject: MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in
 Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)

Analysis: KILL_QUERY is not ignored when local memory used exceeds maximum
session memory. Hence the query proceeds, OK is sent and we end up
reopening tables that are marked for reopen. During this, kill status is
eventually checked and assertion failure happens during trying to send error
message because OK has already been sent.
Fix: Ok is already sent so statement has already executed. It is too
late to give error. So ignore kill.
---
 mysql-test/main/alter_table.result | 18 ++++++++++++++++++
 mysql-test/main/alter_table.test   | 22 ++++++++++++++++++++++
 sql/lock.cc                        |  2 +-
 sql/sql_base.cc                    |  4 +++-
 4 files changed, 44 insertions(+), 2 deletions(-)

diff --git a/mysql-test/main/alter_table.result b/mysql-test/main/alter_table.result
index 755de4336b9..682f2cc9d82 100644
--- a/mysql-test/main/alter_table.result
+++ b/mysql-test/main/alter_table.result
@@ -3415,5 +3415,23 @@ ERROR 0A000: ALGORITHM=INPLACE is not supported for this operation. Try ALGORITH
 delete from t1 where a = 11;
 drop table t1;
 #
+# MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in
+# Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)
+#
+SET @max_session_mem_used_save= @@max_session_mem_used;
+CREATE TABLE t1 (a INT);
+SELECT * FROM t1;
+a
+ALTER TABLE x MODIFY xx INT;
+ERROR 42S02: Table 'test.x' doesn't exist
+SET SESSION max_session_mem_used= 8192;
+LOCK TABLE t1 WRITE;
+ALTER TABLE t1 CHANGE COLUMN IF EXISTS b c INT;
+Warnings:
+Note	1054	Unknown column 'b' in 't1'
+SET SESSION max_session_mem_used = @max_session_mem_used_save;
+UNLOCK TABLES;
+DROP TABLE t1;
+#
 # End of 10.5 tests
 #
diff --git a/mysql-test/main/alter_table.test b/mysql-test/main/alter_table.test
index 1bff20a7bd7..cc17c3efec9 100644
--- a/mysql-test/main/alter_table.test
+++ b/mysql-test/main/alter_table.test
@@ -2661,6 +2661,28 @@ delete from t1 where a = 11;
 # cleanup
 drop table t1;
 
+--echo #
+--echo # MDEV-23836: Assertion `! is_set() || m_can_overwrite_status' in
+--echo # Diagnostics_area::set_error_status (interrupted ALTER TABLE under LOCK)
+--echo #
+
+SET @max_session_mem_used_save= @@max_session_mem_used;
+
+CREATE TABLE t1 (a INT);
+SELECT * FROM t1;
+
+--error ER_NO_SUCH_TABLE
+ALTER TABLE x MODIFY xx INT;
+
+SET SESSION max_session_mem_used= 8192;
+LOCK TABLE t1 WRITE;
+
+ALTER TABLE t1 CHANGE COLUMN IF EXISTS b c INT;
+
+SET SESSION max_session_mem_used = @max_session_mem_used_save;
+UNLOCK TABLES;
+DROP TABLE t1;
+
 --echo #
 --echo # End of 10.5 tests
 --echo #
diff --git a/sql/lock.cc b/sql/lock.cc
index 559f1195b32..ec91655375e 100644
--- a/sql/lock.cc
+++ b/sql/lock.cc
@@ -356,7 +356,7 @@ bool mysql_lock_tables(THD *thd, MYSQL_LOCK *sql_lock, uint flags)
 end:
   THD_STAGE_INFO(thd, org_stage);
 
-  if (thd->killed)
+  if (thd->killed && !thd->get_stmt_da()->is_ok())
   {
     thd->send_kill_message();
     if (!rc)
diff --git a/sql/sql_base.cc b/sql/sql_base.cc
index 01e8a65fda4..87d7f65fed5 100644
--- a/sql/sql_base.cc
+++ b/sql/sql_base.cc
@@ -2609,7 +2609,9 @@ void Locked_tables_list::mark_table_for_reopen(THD *thd, TABLE *table)
 bool
 Locked_tables_list::reopen_tables(THD *thd, bool need_reopen)
 {
-  Open_table_context ot_ctx(thd, MYSQL_OPEN_REOPEN);
+  bool is_ok= thd->get_stmt_da()->is_ok();
+  Open_table_context ot_ctx(thd, !is_ok ? MYSQL_OPEN_REOPEN:
+                                  MYSQL_OPEN_IGNORE_KILLED | MYSQL_OPEN_REOPEN);
   uint reopen_count= 0;
   MYSQL_LOCK *lock;
   MYSQL_LOCK *merged_lock;
-- 
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