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MDEV-4422 SHOW PROCESSLIST reference to THD::db not protected against simultaneous updates

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protect THD::db with THD::LOCK_thd_data
This commit is contained in:
Sergei Golubchik 2013-06-12 20:29:19 +02:00
parent f722b15dc2
commit dacb3809a2
2 changed files with 12 additions and 4 deletions
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12
sql/sql_class.h
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@ -1605,6 +1605,7 @@ public:
Protects THD data accessed from other threads:
- thd->query and thd->query_length (used by SHOW ENGINE
INNODB STATUS and SHOW PROCESSLIST
- thd->db and thd->db_length (used in SHOW PROCESSLIST)
- thd->mysys_var (used by KILL statement and shutdown).
Is locked when THD is deleted.
*/
@ -2838,6 +2839,7 @@ public:
*/
bool set_db(const char *new_db, size_t new_db_len)
{
mysql_mutex_lock(&LOCK_thd_data);
/* Do not reallocate memory if current chunk is big enough. */
if (db && new_db && db_length >= new_db_len)
memcpy(db, new_db, new_db_len+1);
@ -2850,6 +2852,7 @@ public:
db= NULL;
}
db_length= db ? new_db_len : 0;
mysql_mutex_unlock(&LOCK_thd_data);
return new_db && !db;
}
@ -2866,8 +2869,13 @@ public:
*/
void reset_db(char *new_db, size_t new_db_len)
{
db= new_db;
db_length= new_db_len;
if (new_db != db || new_db_len != db_length)
{
mysql_mutex_lock(&LOCK_thd_data);
db= new_db;
db_length= new_db_len;
mysql_mutex_unlock(&LOCK_thd_data);
}
}
/*
Copy the current database to the argument. Use the current arena to

4
sql/sql_show.cc
View File

@ -2212,10 +2212,10 @@ void mysqld_list_processes(THD *thd,const char *user, bool verbose)
thd_info->host= thd->strdup(tmp_sctx->host_or_ip[0] ?
tmp_sctx->host_or_ip :
tmp_sctx->host ? tmp_sctx->host : "");
if ((thd_info->db=tmp->db)) // Safe test
thd_info->db=thd->strdup(thd_info->db);
thd_info->command=(int) tmp->command;
mysql_mutex_lock(&tmp->LOCK_thd_data);
if ((thd_info->db= tmp->db)) // Safe test
thd_info->db= thd->strdup(thd_info->db);
if ((mysys_var= tmp->mysys_var))
mysql_mutex_lock(&mysys_var->mutex);
thd_info->proc_info= (char*) (tmp->killed >= KILL_QUERY ?