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authorSergey Vojtovich <svoj@mariadb.org>2015-06-09 13:50:43 +0400
committerSergey Vojtovich <svoj@mariadb.org>2015-06-09 23:24:02 +0400
commit3a50a8c9bed9163beb3373cee8e2a51b3550b72e (patch)
tree80b15d1c83e246d18c94fb5e820ab7c2a2c568d8 /sql
parent49a3392441c1e44385516185a239addf8e0421d7 (diff)
downloadmariadb-git-3a50a8c9bed9163beb3373cee8e2a51b3550b72e.tar.gz
MDEV-363 - Server crashes in intern_plugin_lock on concurrent installing
semisync plugin and setting rpl_semi_sync_master_enabled There was race condition between INSTALL PLUGIN and SET. It was caused by a gap in INSTALL PLUGIN when plugin variables were registered but not fully initialized. Accessing such variables concurrently may reference uninitialized memory, specifically sys_var_pluginvar::plugin. Fixed by initializing sys_var_pluginvar::plugin early, before variable is registered.
Diffstat (limited to 'sql')
-rw-r--r--sql/sql_plugin.cc26
1 files changed, 6 insertions, 20 deletions
diff --git a/sql/sql_plugin.cc b/sql/sql_plugin.cc
index 6503910079d..dbbc2622866 100644
--- a/sql/sql_plugin.cc
+++ b/sql/sql_plugin.cc
@@ -271,13 +271,15 @@ public:
{ TRASH(ptr_arg, size); }
sys_var_pluginvar(sys_var_chain *chain, const char *name_arg,
- struct st_mysql_sys_var *plugin_var_arg)
+ struct st_mysql_sys_var *plugin_var_arg,
+ struct st_plugin_int *plugin_arg)
:sys_var(chain, name_arg, plugin_var_arg->comment,
(plugin_var_arg->flags & PLUGIN_VAR_THDLOCAL ? SESSION : GLOBAL) |
(plugin_var_arg->flags & PLUGIN_VAR_READONLY ? READONLY : 0),
0, -1, NO_ARG, pluginvar_show_type(plugin_var_arg), 0, 0,
VARIABLE_NOT_IN_BINLOG, NULL, NULL, NULL),
- plugin_var(plugin_var_arg), orig_pluginvar_name(plugin_var_arg->name)
+ plugin(plugin_arg), plugin_var(plugin_var_arg),
+ orig_pluginvar_name(plugin_var_arg->name)
{ plugin_var->name= name_arg; }
sys_var_pluginvar *cast_pluginvar() { return this; }
bool check_update_type(Item_result type);
@@ -1407,22 +1409,6 @@ static int plugin_initialize(MEM_ROOT *tmp_root, struct st_plugin_int *plugin,
#endif /* FIX_LATER */
}
- /*
- set the plugin attribute of plugin's sys vars so they are pointing
- to the active plugin
- */
- if (plugin->system_vars)
- {
- sys_var_pluginvar *var= plugin->system_vars->cast_pluginvar();
- for (;;)
- {
- var->plugin= plugin;
- if (!var->next)
- break;
- var= var->next->cast_pluginvar();
- }
- }
-
ret= 0;
err:
@@ -3925,7 +3911,7 @@ static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
if (o->flags & PLUGIN_VAR_NOSYSVAR)
continue;
if ((var= find_bookmark(plugin_name.str, o->name, o->flags)))
- v= new (mem_root) sys_var_pluginvar(&chain, var->key + 1, o);
+ v= new (mem_root) sys_var_pluginvar(&chain, var->key + 1, o, tmp);
else
{
len= plugin_name.length + strlen(o->name) + 2;
@@ -3933,7 +3919,7 @@ static int test_plugin_options(MEM_ROOT *tmp_root, struct st_plugin_int *tmp,
strxmov(varname, plugin_name.str, "-", o->name, NullS);
my_casedn_str(&my_charset_latin1, varname);
convert_dash_to_underscore(varname, len-1);
- v= new (mem_root) sys_var_pluginvar(&chain, varname, o);
+ v= new (mem_root) sys_var_pluginvar(&chain, varname, o, tmp);
}
DBUG_ASSERT(v); /* check that an object was actually constructed */
} /* end for */