MDEV-21398 Deadlock (server hang) or assertion failure in
Diagnostics_area::set_error_status upon ALTER under lock
This failure could only happen if one locked the same table
multiple times and then did an ALTER TABLE on the table.
Major change is to change all instances of
table->m_needs_reopen= true;
to
table->mark_table_for_reopen();
The main fix for the problem was to ensure that we mark all
instances of the table in the locked_table_list and when we
reopen the tables, we first close all tables before reopening
and locking them.
Other things:
- Don't call thd->locked_tables_list.reopen_tables if there
are no tables marked for reopen. (performance)
check_valid_path() uses my_strcspn() that cannot handle invalid characters
properly. This is fixed by a big refactoring in 10.2 (MDEV-6353).
For 5.5, let's simply swap tests, because check_string_char_length()
rejects invalid characters just fine.
Description:- During server startup, the server exits if
the 'mysql.plugin' system table has any rows with empty
value for the field 'name' (plugin name).
Plugin fixed to not lock the LOCK_operations when not active.
Server fixed to lock the LOCK_plugin less - do it once per
thread and then only if a plugin was installed/uninstalled.
Solve 3 way deadlock between plugin_initialiaze(), THD::init() and
mysql_sys_var_char().
The deadlock exists because of the lock order inversion between
LOCK_global_system_variables mutex and LOCK_system_variables_hash
read-write lock-
In this case, it is enough to change LOCK_system_variables_hash to prefer
reads to fix the deadlock, i.e change it to mysql_prlock_t
TRASH was mapped to TRASH_FREE and was supposed to be used for memory
that should not be accessed anymore, while TRASH_ALLOC() is to be
used for uninitialized but to-be-used memory.
But sometimes TRASH() was used in the latter sense.
Remove TRASH() macro, always use explicit TRASH_ALLOC() or TRASH_FREE().
Moved TOI replication to happen after ACL checking for commands:
SQLCOM_CREATE_EVENT
SQLCOM_ALTER_EVENT
SQLCOM_DROP_EVENT
SQLCOM_CREATE_VIEW
SQLCOM_CREATE_TRIGGER
SQLCOM_DROP_TRIGGER
SQLCOM_INSTALL_PLUGIN
SQLCOM_UNINSTALL_PLUGIN
IS DROPPED
ANALYSIS:
=========
It is advised not to tamper with the system tables.
When primary key is dropped from a system table, certain
operations on the table which tries to access the table key
information may lead to server exit.
FIX:
====
An appropriate error is now reported in such a case.
in buildbot
Removed plugin_array_version: it is being checked without mutex protection and
thus is prone to data race and race conditions. In effect plugins are not
protected from concurrent destruction.
Removed state_mask inversion: doesn't seem to make any sense.
When collecting local plugins list, only add plugins that match state_mask.
Use plugin ref counting to protect against concurrent plugin destruction.
Moved TOI replication to happen after ACL checking for commands:
SQLCOM_CREATE_EVENT
SQLCOM_ALTER_EVENT
SQLCOM_DROP_EVENT
SQLCOM_CREATE_VIEW
SQLCOM_CREATE_TRIGGER
SQLCOM_DROP_TRIGGER
SQLCOM_INSTALL_PLUGIN
SQLCOM_UNINSTALL_PLUGIN
- Fix win64 pointer truncation warnings
(usually coming from misusing 0x%lx and long cast in DBUG)
- Also fix printf-format warnings
Make the above mentioned warnings fatal.
- fix pthread_join on Windows to set return value.
