bk commit into 5.0 tree (msvensson:1.2137) BUG#19938

[msvensson]

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ChangeSet
  1.2137 06/05/23 10:20:57 msvensson@neptunus.(none) +1 -0
  Bug#19938  Valgrind error (race) in handle_slave_sql()
   - Unlock the mutex after looking at rli->events_till_abort
   - Already fixed in 5.1 so it will be null merged.

  sql/slave.cc
    1.266 06/05/23 10:20:49 msvensson@neptunus.(none) +11 -2
    Unlock the mutex after looking at rli->events_till_abort

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	msvensson
# Host:	neptunus.(none)
# Root:	/home/msvensson/mysql/mysql-5.0

--- 1.265/sql/slave.cc	2006-02-17 07:51:10 +01:00
+++ 1.266/sql/slave.cc	2006-05-23 10:20:49 +02:00
@@ -3950,11 +3950,20 @@
   pthread_mutex_unlock(&LOCK_thread_count);
   pthread_cond_broadcast(&rli->stop_cond);
   // tell the world we are done
-  pthread_mutex_unlock(&rli->run_lock);
+
 #ifndef DBUG_OFF // TODO: reconsider the code below
   if (abort_slave_event_count && !rli->events_till_abort)
+  {
+    /*
+      Bug #19938 Valgrind error (race) in handle_slave_sql()
+      Read the value of rli->event_till_abort before releasing the mutex
+    */
+    pthread_mutex_unlock(&rli->run_lock);
     goto slave_begin;
-#endif  
+  }
+#endif
+  pthread_mutex_unlock(&rli->run_lock);
+
   my_thread_end();
   pthread_exit(0);
   DBUG_RETURN(0);				// Can't return anything here