Commit 5daff654 authored by sven@murkla.(none)'s avatar sven@murkla.(none)
Browse files

BUG#30752 rpl_dual_pos_advance valgrind (jump depends on uninitialized LOG_INFO) 

Problem: one thread could read uninitialized memory from (the stack of) another
thread.
Fix: swapped order of initializing the memory and making it available to the
other thread.
Fix: put lock around the statement that makes the memory available to the other
thread.
Fix: all fields of the struct are now initialized in the constructor, to avoid
future problems.
parent 5efd35b0

sql/sql_class.h

+7 −1
Original line number Diff line number Diff line
@@ -159,7 +159,13 @@ typedef struct st_log_info 
  my_off_t pos;

  bool fatal; // if the purge happens to give us a negative offset

  pthread_mutex_t lock;

  st_log_info():fatal(0) { pthread_mutex_init(&lock, MY_MUTEX_INIT_FAST);}

  st_log_info()

    : index_file_offset(0), index_file_start_offset(0),

      pos(0), fatal(0)

  {

    log_file_name[0] = '\0';

    pthread_mutex_init(&lock, MY_MUTEX_INIT_FAST);

  }

  ~st_log_info() { pthread_mutex_destroy(&lock);}

} LOG_INFO;

sql/sql_repl.cc

+8 −2
Original line number Diff line number Diff line
@@ -364,7 +364,6 @@ void mysql_binlog_send(THD* thd, char* log_ident, my_off_t pos, 
    name=0;					// Find first log



  linfo.index_file_offset = 0;

  thd->current_linfo = &linfo;



  if (mysql_bin_log.find_log_pos(&linfo, name, 1))

  {
@@ -373,6 +372,10 @@ void mysql_binlog_send(THD* thd, char* log_ident, my_off_t pos, 
    goto err;

  }



  pthread_mutex_lock(&LOCK_thread_count);

  thd->current_linfo = &linfo;

  pthread_mutex_unlock(&LOCK_thread_count);



  if ((file=open_binlog(&log, log_file_name, &errmsg)) < 0)

  {

    my_errno= ER_MASTER_FATAL_ERROR_READING_BINLOG;
@@ -1338,7 +1341,6 @@ bool mysql_show_binlog_events(THD* thd) 
      name=0;					// Find first log



    linfo.index_file_offset = 0;

    thd->current_linfo = &linfo;



    if (mysql_bin_log.find_log_pos(&linfo, name, 1))

    {
@@ -1346,6 +1348,10 @@ bool mysql_show_binlog_events(THD* thd) 
      goto err;

    }



    pthread_mutex_lock(&LOCK_thread_count);

    thd->current_linfo = &linfo;

    pthread_mutex_unlock(&LOCK_thread_count);



    if ((file=open_binlog(&log, linfo.log_file_name, &errmsg)) < 0)

      goto err;