From 65c632cb9cf44aea8132b65cc7a08253ec4282af Mon Sep 17 00:00:00 2001
From: Andrei Elkin <andrei.elkin@mariadb.com>
Date: Tue, 29 Sep 2020 19:12:00 +0300
Subject: [PATCH] MDEV-23832 Crash at startup in Log_event::read_log_event

The crash was caused by improper raising of an error or replication checksum
verification at time of the server initialization. As there is no THD object
associated with the main initializing thread yet the error text should be
assigned with calling a respective macro that is aware of that possibility.

Fixed accordingly.

[At merging to 10.4 the new test result file needs
 +# restart: --master_verify_checksum=ON --debug_dbug=+d,corrupt_read_log_event_char
that mtr run will hint on.]
---
 .../r/binlog_recover_checksum_error.result    |  7 ++++
 .../t/binlog_recover_checksum_error.test      | 37 +++++++++++++++++++
 sql/log_event.cc                              |  2 +-
 3 files changed, 45 insertions(+), 1 deletion(-)
 create mode 100644 mysql-test/suite/binlog/r/binlog_recover_checksum_error.result
 create mode 100644 mysql-test/suite/binlog/t/binlog_recover_checksum_error.test

diff --git a/mysql-test/suite/binlog/r/binlog_recover_checksum_error.result b/mysql-test/suite/binlog/r/binlog_recover_checksum_error.result
new file mode 100644
index 00000000000..f65f7797d7f
--- /dev/null
+++ b/mysql-test/suite/binlog/r/binlog_recover_checksum_error.result
@@ -0,0 +1,7 @@
+set @@global.binlog_checksum = CRC32;
+call mtr.add_suppression("Replication event checksum verification failed");
+call mtr.add_suppression("Error in Log_event::read_log_event");
+set @@global.debug_dbug = VALUE;
+set @@global.master_verify_checksum = DO_CHECKSUM;
+set @@global.binlog_checksum = BINLOG_CHECKSUM;
+# EOF the test
diff --git a/mysql-test/suite/binlog/t/binlog_recover_checksum_error.test b/mysql-test/suite/binlog/t/binlog_recover_checksum_error.test
new file mode 100644
index 00000000000..12c9f3d914f
--- /dev/null
+++ b/mysql-test/suite/binlog/t/binlog_recover_checksum_error.test
@@ -0,0 +1,37 @@
+# The test verifies server binlog-based recovery.
+#
+# MDEV-23832 checksum error at server binlog recovery should not crash
+
+# The test logic really requires --log-bin.
+--source include/have_binlog_format_mixed.inc
+--source include/have_debug.inc
+
+--let $do_checksum = `SELECT @@global.master_verify_checksum`
+--let $debug_dbug_saved = `SELECT @@global.debug_dbug`
+--let $binlog_checksum = `SELECT @@global.binlog_checksum`
+set @@global.binlog_checksum = CRC32;
+
+call mtr.add_suppression("Replication event checksum verification failed");
+call mtr.add_suppression("Error in Log_event::read_log_event");
+
+# Proof of no crash follows.
+# There's no need for actual bin-loggable queries to the server
+--let $restart_parameters=  --master_verify_checksum=ON --debug_dbug="+d,corrupt_read_log_event_char"
+--let $shutdown_timeout=0
+--source include/restart_mysqld.inc
+--let $restart_parameters=
+--let $shutdown_timeout=
+
+#
+# Cleanup
+
+--replace_regex /= .*/= VALUE/
+--eval set @@global.debug_dbug = "$debug_dbug_saved"
+
+--replace_result $do_checksum DO_CHECKSUM
+--eval set @@global.master_verify_checksum = $do_checksum
+--replace_result $binlog_checksum BINLOG_CHECKSUM
+--eval set @@global.binlog_checksum = $binlog_checksum
+#
+--echo # EOF the test
+#
diff --git a/sql/log_event.cc b/sql/log_event.cc
index 3d28c249e21..146d8bd5dbe 100644
--- a/sql/log_event.cc
+++ b/sql/log_event.cc
@@ -1632,7 +1632,7 @@ Log_event* Log_event::read_log_event(const char* buf, uint event_len,
     else
       DBUG_RETURN(NULL);
 #else
-    *error= ER(ER_BINLOG_READ_EVENT_CHECKSUM_FAILURE);
+    *error= ER_THD_OR_DEFAULT(current_thd, ER_BINLOG_READ_EVENT_CHECKSUM_FAILURE);
     sql_print_error("%s", *error);
     DBUG_RETURN(NULL);
 #endif