Commit c57b8bde authored by sasha@mysql.sashanet.com's avatar sasha@mysql.sashanet.com
Browse files

sql/mysqld.cc 

    fixed concurrency bug with a very quickly disconnecting client -
    the client could disconnect and delete thd before pthread_create 
    could write to &thd->real_id 
sql/sql_list.h
    while tracking down the bug, made new/delete go through my_malloc/my_free
    for ilink - did not help, but this is better anyway - cleaner exit with a message in
    out of memory codition at least.
parent 5487d7a8

sql/mysqld.cc

+2 −2
Original line number Diff line number Diff line
@@ -2091,7 +2091,6 @@ static void create_new_thread(THD *thd) 
      threads.append(thd);

      DBUG_PRINT("info",(("creating thread %d"), thd->thread_id));

      thd->connect_time = time(NULL);

      (void) pthread_mutex_unlock(&LOCK_thread_count);

      if ((error=pthread_create(&thd->real_id,&connection_attrib,

				handle_one_connection,

				(void*) thd)))
@@ -2099,7 +2098,6 @@ static void create_new_thread(THD *thd) 
	DBUG_PRINT("error",

		   ("Can't create thread to handle request (error %d)",

		    error));

	(void) pthread_mutex_lock(&LOCK_thread_count);

	thread_count--;

	thd->killed=1;				// Safety

	(void) pthread_mutex_unlock(&LOCK_thread_count);
@@ -2110,6 +2108,8 @@ static void create_new_thread(THD *thd) 
	(void) pthread_mutex_unlock(&LOCK_thread_count);

	DBUG_VOID_RETURN;

      }

      

      (void) pthread_mutex_unlock(&LOCK_thread_count);

    }

  }

  DBUG_PRINT("info",(("Thread %d created"), thd->thread_id));

sql/sql_list.h

+9 −0
Original line number Diff line number Diff line
@@ -225,6 +225,15 @@ template <class T> class List_iterator :public base_list_iterator 


struct ilink {

  struct ilink **prev,*next;

  static void *operator new(size_t size)

  {

    return (void*)my_malloc((uint)size, MYF(MY_WME | MY_FAE));

  }

  static void operator delete(void* ptr_arg, size_t size)

  {

     my_free((gptr)ptr_arg, MYF(MY_WME|MY_ALLOW_ZERO_PTR));

  }



  inline ilink()

  {

    prev=0; next=0;