MDEV-26556 An improper locking bug(s) due to unreleased lock.

Get rid of the global big_buffer.

mysql-test/suite/plugins/r/server_audit.result

@@ -261,6 +261,9 @@ A	B	C	D
 A	B	C	D
 set global server_audit_query_log_limit= 1024;
 drop database sa_db;
+select length('01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789');
+length('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456
+2750
 set global server_audit_file_path='.';
 show status like 'server_audit_current_log';
 Variable_name	Value
@@ -485,6 +488,7 @@ TIME,HOSTNAME,root,localhost,ID,ID,READ,mysql,proc,
 TIME,HOSTNAME,root,localhost,ID,ID,WRITE,mysql,proc,
 TIME,HOSTNAME,root,localhost,ID,ID,WRITE,mysql,event,
 TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'drop database sa_db',0
+TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'select length(\'012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567',0
 TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'set global server_audit_file_path=\'.\'',0
 TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'set global server_audit_file_path=\'.\'',0
 TIME,HOSTNAME,root,localhost,ID,ID,QUERY,sa_db,'show status like \'server_audit_current_log\'',0

mysql-test/suite/plugins/t/server_audit.test

@@ -210,6 +210,8 @@ select 'A', 'B', 'C', 'D';
 set global server_audit_query_log_limit= 1024;
 drop database sa_db;
 
+select length('01234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789');
+
 set global server_audit_file_path='.';
 --replace_regex /\.[\\\/]/HOME_DIR\//
 show status like 'server_audit_current_log';

plugin/server_audit/server_audit.c

@@ -301,8 +301,6 @@ static char logging;
 static volatile int internal_stop_logging= 0;
 static char incl_user_buffer[1024];
 static char excl_user_buffer[1024];
-static char *big_buffer= NULL;
-static size_t big_buffer_alloced= 0;
 static unsigned int query_log_limit= 0;
 
 static char servhost[256];
@@ -555,20 +553,16 @@ static struct st_mysql_show_var audit_status[]=
 /* These belong to the service initialization */
 static PSI_mutex_key key_LOCK_operations;
 static PSI_mutex_key key_LOCK_atomic;
-static PSI_mutex_key key_LOCK_bigbuffer;
 static PSI_mutex_info mutex_key_list[]=
 {
   { &key_LOCK_operations, "SERVER_AUDIT_plugin::lock_operations",
     PSI_FLAG_GLOBAL},
   { &key_LOCK_atomic, "SERVER_AUDIT_plugin::lock_atomic",
     PSI_FLAG_GLOBAL},
-  { &key_LOCK_bigbuffer, "SERVER_AUDIT_plugin::lock_bigbuffer",
-    PSI_FLAG_GLOBAL}
 };
 #endif
 static mysql_mutex_t lock_operations;
 static mysql_mutex_t lock_atomic;
-static mysql_mutex_t lock_bigbuffer;
 
 /* The Percona server and partly MySQL don't support         */
 /* launching client errors in the 'update_variable' methods. */
@@ -1700,7 +1694,7 @@ static int log_statement_ex(const struct connection_info *cn,
                             int error_code, const char *type, int take_lock)
 {
   size_t csize;
-  char message_loc[1024];
+  char message_loc[2048];
   char *message= message_loc;
   size_t message_size= sizeof(message_loc);
   char *uh_buffer;
@@ -1709,6 +1703,7 @@ static int log_statement_ex(const struct connection_info *cn,
   unsigned int db_length;
   long long query_id;
   int result;
+  char *big_buffer= NULL;
 
   if ((db= cn->db))
     db_length= cn->db_length;
@@ -1791,17 +1786,9 @@ static int log_statement_ex(const struct connection_info *cn,
 
   if (query_len > (message_size - csize)/2)
   {
-    flogger_mutex_lock(&lock_bigbuffer);
-    if (big_buffer_alloced < (query_len * 2 + csize))
-    {
-      big_buffer_alloced= (query_len * 2 + csize + 4095) & ~4095L;
-      big_buffer= realloc(big_buffer, big_buffer_alloced);
-      if (big_buffer == NULL)
-      {
-        big_buffer_alloced= 0;
-        return 0;
-      }
-    }
+    size_t big_buffer_alloced= (query_len * 2 + csize + 4095) & ~4095L;
+    if(!(big_buffer= malloc(big_buffer_alloced)))
+      return 0;
 
     memcpy(big_buffer, message, csize);
     message= big_buffer;
@@ -1846,8 +1833,8 @@ static int log_statement_ex(const struct connection_info *cn,
                       "\',%d", error_code);
   message[csize]= '\n';
   result= write_log(message, csize + 1, take_lock);
-  if (message == big_buffer)
-    flogger_mutex_unlock(&lock_bigbuffer);
+  if (big_buffer)
+    free(big_buffer);
 
   return result;
 }
@@ -2496,7 +2483,6 @@ static int server_audit_init(void *p __attribute__((unused)))
 #endif
   flogger_mutex_init(key_LOCK_operations, &lock_operations, MY_MUTEX_INIT_FAST);
   flogger_mutex_init(key_LOCK_operations, &lock_atomic, MY_MUTEX_INIT_FAST);
-  flogger_mutex_init(key_LOCK_operations, &lock_bigbuffer, MY_MUTEX_INIT_FAST);
 
   coll_init(&incl_user_coll);
   coll_init(&excl_user_coll);
@@ -2581,10 +2567,8 @@ static int server_audit_deinit(void *p __attribute__((unused)))
   else if (output_type == OUTPUT_SYSLOG)
     closelog();
 
-  (void) free(big_buffer);
   flogger_mutex_destroy(&lock_operations);
   flogger_mutex_destroy(&lock_atomic);
-  flogger_mutex_destroy(&lock_bigbuffer);
 
   error_header();
   fprintf(stderr, "STOPPED\n");