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author | Sergey Vojtovich <svoj@mariadb.org> | 2015-06-09 13:50:43 +0400 |
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committer | Sergey Vojtovich <svoj@mariadb.org> | 2015-06-09 23:24:02 +0400 |
commit | 3a50a8c9bed9163beb3373cee8e2a51b3550b72e (patch) | |
tree | 80b15d1c83e246d18c94fb5e820ab7c2a2c568d8 /sql | |
parent | 49a3392441c1e44385516185a239addf8e0421d7 (diff) | |
download | mariadb-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.cc | 26 |
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 */ |