Bug#18903155: BACKPORT BUG-18008907 TO 5.5+ VERSIONS.

Backporting patch committed for bug 18008907 to 5.5
and 5.6.

2 files changed, 187 insertions, 0 deletions

diff --git a/mysql-test/r/plugin.result b/mysql-test/r/plugin.result
index 2b96dc4f3ac..03a1ab70278 100644
--- a/mysql-test/r/plugin.result
+++ b/mysql-test/r/plugin.result
@@ -143,3 +143,73 @@ SELECT @@SESSION.example_double_thdvar;
 @@SESSION.example_double_thdvar
 1000.500000
 UNINSTALL PLUGIN example;
+#
+# BUG#18008907 - DEADLOCK BETWEEN MYSQL_CHANGE_USER(), SHOW VARIABLES AND INSTALL PLUGIN
+#
+CREATE PROCEDURE p_install()
+BEGIN
+INSTALL PLUGIN no_such_plugin SONAME 'no_such_object';
+END
+|
+CREATE PROCEDURE p_show_vars()
+BEGIN
+SELECT COUNT(*) FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES;
+END|
+connect con1, localhost, root,,;
+# Case 18008907_1: Deadlock situation cause by
+#                  con1: has LOCK_system_variables_hash and waits on LOCK_plugin  AND
+#                  default: has LOCK_plugin and waits on LOCK_system_variables_hash.
+#
+SET DEBUG_SYNC='acquired_LOCK_system_variables_hash SIGNAL install_plugin WAIT_FOR cont_show_vars';
+call p_show_vars();;
+connection default;
+SET DEBUG_SYNC='now WAIT_FOR install_plugin';
+SET DEBUG_SYNC='acquired_LOCK_plugin SIGNAL cont_show_vars';
+call p_install();;
+connection con1;
+COUNT(*)
+#
+SET DEBUG_SYNC='RESET';
+connection default;
+ERROR HY000: Can't open shared library
+SET DEBUG_SYNC='RESET';
+# Case 18008907_2: Deadlock situation caused by
+#                  default: has LOCK_system_variables_hash and waits on LOCK_global_system_variables,
+#                  con1: has LOCK_plugin and waits on LOCK_system_variables_hash AND
+#                  con2: has LOCK_global_system_variables and waits on LOCK_plugin.
+SET DEBUG_SYNC='acquired_LOCK_system_variables_hash SIGNAL install_plugin WAIT_FOR nothing TIMEOUT 10';
+call p_show_vars();;
+connection con1;
+SET DEBUG_SYNC='now WAIT_FOR install_plugin';
+SET DEBUG_SYNC='acquired_LOCK_plugin SIGNAL create_connection WAIT_FOR nothing TIMEOUT 10';
+call p_install();;
+connect con2, localhost, root,,;
+SET DEBUG_SYNC='now WAIT_FOR create_connection';
+connection con1;
+ERROR HY000: Can't open shared library
+connection default;
+COUNT(*)
+#
+Warnings:
+#	1639	debug sync point wait timed out
+disconnect con2;
+# Case 18008907_3: Testing Concurrent "Show Variables" and "Plugin Uninstall" operations.
+INSTALL PLUGIN example SONAME 'ha_example.so';
+connection con1;
+SET DEBUG_SYNC='acquired_LOCK_system_variables_hash SIGNAL uninstall_plugin WAIT_FOR go';
+call p_show_vars();;
+connect con2, localhost, root,,;
+SET DEBUG_SYNC='now WAIT_FOR uninstall_plugin';
+UNINSTALL PLUGIN example;;
+connection default;
+SET DEBUG_SYNC='now SIGNAL go';
+connection con1;
+COUNT(*)
+#
+connection con2;
+connection default;
+DROP PROCEDURE p_show_vars;
+DROP PROCEDURE p_install;
+SET DEBUG_SYNC='RESET';
+disconnect con1;
+disconnect con2;
diff --git a/mysql-test/t/plugin.test b/mysql-test/t/plugin.test
index f3a3b0cc068..c9220651fa8 100644
--- a/mysql-test/t/plugin.test
+++ b/mysql-test/t/plugin.test
@@ -1,5 +1,7 @@
+#
 --source include/not_windows_embedded.inc
 --source include/have_example_plugin.inc
+--source include/have_debug_sync.inc
 
 CREATE TABLE t1(a int) ENGINE=EXAMPLE;
 DROP TABLE t1;
@@ -137,3 +139,118 @@ SET SESSION example_double_thdvar = 1000.51;
 SELECT @@SESSION.example_double_thdvar;
 
 UNINSTALL PLUGIN example;
+
+--echo #
+--echo # BUG#18008907 - DEADLOCK BETWEEN MYSQL_CHANGE_USER(), SHOW VARIABLES AND INSTALL PLUGIN
+--echo #
+
+--enable_connect_log
+
+delimiter |;
+
+CREATE PROCEDURE p_install()
+BEGIN
+  INSTALL PLUGIN no_such_plugin SONAME 'no_such_object';
+END
+|
+
+CREATE PROCEDURE p_show_vars()
+BEGIN
+  SELECT COUNT(*) FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES;
+END|
+
+delimiter ;|
+
+connect(con1, localhost, root,,);
+
+--echo # Case 18008907_1: Deadlock situation cause by
+--echo #                  con1: has LOCK_system_variables_hash and waits on LOCK_plugin  AND
+--echo #                  default: has LOCK_plugin and waits on LOCK_system_variables_hash.
+--echo #
+SET DEBUG_SYNC='acquired_LOCK_system_variables_hash SIGNAL install_plugin WAIT_FOR cont_show_vars';
+--send call p_show_vars();
+
+connection default;
+SET DEBUG_SYNC='now WAIT_FOR install_plugin';
+SET DEBUG_SYNC='acquired_LOCK_plugin SIGNAL cont_show_vars';
+--send call p_install();
+
+connection con1;
+# Without fix, reap will hang.
+--replace_column 1 #
+--reap;
+SET DEBUG_SYNC='RESET';
+
+connection default;
+--replace_regex /(Can\'t open shared library).*$/\1/
+--error ER_CANT_OPEN_LIBRARY
+--reap;
+SET DEBUG_SYNC='RESET';
+
+--echo # Case 18008907_2: Deadlock situation caused by
+--echo #                  default: has LOCK_system_variables_hash and waits on LOCK_global_system_variables,
+--echo #                  con1: has LOCK_plugin and waits on LOCK_system_variables_hash AND
+--echo #                  con2: has LOCK_global_system_variables and waits on LOCK_plugin.
+
+SET DEBUG_SYNC='acquired_LOCK_system_variables_hash SIGNAL install_plugin WAIT_FOR nothing TIMEOUT 10';
+--send call p_show_vars();
+
+connection con1;
+SET DEBUG_SYNC='now WAIT_FOR install_plugin';
+SET DEBUG_SYNC='acquired_LOCK_plugin SIGNAL create_connection WAIT_FOR nothing TIMEOUT 10';
+--send call p_install();
+
+connect(con2, localhost, root,,);
+SET DEBUG_SYNC='now WAIT_FOR create_connection';
+# Without fix, deadlock situation will occur on timeout of debug_syncs in
+# default and con1.  Because of this, change_user operation hangs.
+change_user;
+
+connection con1;
+--replace_regex /(Can\'t open shared library).*$/\1/
+--error ER_CANT_OPEN_LIBRARY
+--reap;
+
+connection default;
+--replace_column 1 #
+--reap;
+disconnect con2;
+
+--echo # Case 18008907_3: Testing Concurrent "Show Variables" and "Plugin Uninstall" operations.
+
+#Installing plugin
+--replace_regex /\.dll/.so/
+eval INSTALL PLUGIN example SONAME '$EXAMPLE_PLUGIN';
+
+connection con1;
+#Acquiring LOCK_system_variables_hash and LOCK_plugin_delete
+SET DEBUG_SYNC='acquired_LOCK_system_variables_hash SIGNAL uninstall_plugin WAIT_FOR go';
+--send call p_show_vars();
+
+connect(con2, localhost, root,,);
+SET DEBUG_SYNC='now WAIT_FOR uninstall_plugin';
+--send UNINSTALL PLUGIN example;
+
+connection default;
+#Plugin Uninstall operation will wait until show variables operations releases LOCK_plugin_delete.
+let $wait_condition= SELECT count(*) = 1 FROM INFORMATION_SCHEMA.PROCESSLIST
+                     WHERE INFO LIKE 'UNINSTALL PLUGIN example' and
+                     STATE LIKE 'Waiting on cond';
+--source include/wait_condition.inc
+SET DEBUG_SYNC='now SIGNAL go';
+
+connection con1;
+--replace_column 1 #
+--reap
+
+connection con2;
+--reap
+
+connection default;
+DROP PROCEDURE p_show_vars;
+DROP PROCEDURE p_install;
+SET DEBUG_SYNC='RESET';
+disconnect con1;
+disconnect con2;
+
+--disable_connect_log