bzr push into mysql-5.6 branch (jon.hauglid:4456 to 4458) Bug#13945257

[Jon Olav Hauglid]

 4458 Jon Olav Hauglid	2012-10-12
      Bug#13945257 NEW COMPILATION ERRORS/WARNINGS WITH XCODE 4.3.2
      
      Follow-up patch: Fix 2 additional warnings reported by Clang 4.1 /
      XCode 4.5.1

    modified:
      sql/item_func.h
      sql/log_event.cc
 4457 Jon Olav Hauglid	2012-10-12
      Bug#14741880: Sporadic query cache related crash in pthread_rwlock_init()
      Bug 67156: Sporadic query cache related crash in pthread_rwlock_init() 
      
      Reinitializing the query cache might lead to a crash inside
      pthread_rwlock_init() on Mac OS X. Mac OS X's pthread_rwlock_init()
      implements a check to detect attempts to reinitialize a previously
      initialized but not yet destroyed read/write lock. This check works by
      looking for a signature within the rwlock object and, if the signature
      matches, some pointer variables within the object are dereferenced.
      
      When MySQL's query cache is resized (e.g. SET query_cache_size = ...),
      or simply deinitialized, the memory used to allocate blocks is freed
      without explicitly deinitializing the allocated blocks. In particular,
      'queries blocks' contain rwlock objects that are not properly destroyed.
      
      If the query cache is resized, and the same memory region is used, and
      a new query block is allocated in the same position, attempting to
      initialize the block's read/write lock might crash if the read-write
      lock object signature was preserved but yet somehow some of its fields
      were corrupted.
      
      The solution is to properly destroy the used read-write lock objects.

    modified:
      sql/sql_cache.cc
 4456 joerg.bruehe@stripped	2012-10-12
      Raise version number after cloning 5.6.8-rc

    modified:
      VERSION
=== modified file 'sql/item_func.h'
--- a/sql/item_func.h	2012-10-10 13:52:42 +0000
+++ b/sql/item_func.h	2012-10-12 14:27:31 +0000
@@ -1686,7 +1686,7 @@ public:
   Item_func_set_user_var(THD *thd, Item_func_set_user_var *item)
     :Item_var_func(thd, item), cached_result_type(item->cached_result_type),
      entry(item->entry), entry_thread_id(item->entry_thread_id),
-     delayed_non_constness(delayed_non_constness), value(item->value),
+     delayed_non_constness(item->delayed_non_constness), value(item->value),
      decimal_buff(item->decimal_buff), null_item(item->null_item),
      save_result(item->save_result), name(item->name)
   {}

=== modified file 'sql/log_event.cc'
--- a/sql/log_event.cc	2012-10-10 13:52:42 +0000
+++ b/sql/log_event.cc	2012-10-12 14:27:31 +0000
@@ -13332,7 +13332,7 @@ size_t my_strmov_quoted_identifier_helpe
 
   if (q == EOF)
   {
-    (void *) strncpy(buffer, identifier, id_length);
+    (void) strncpy(buffer, identifier, id_length);
     return id_length;
   }
   quote_char= (char) q;

=== modified file 'sql/sql_cache.cc'
--- a/sql/sql_cache.cc	2012-10-03 12:51:45 +0000
+++ b/sql/sql_cache.cc	2012-10-12 14:04:45 +0000
@@ -1136,7 +1136,7 @@ ulong Query_cache::resize(ulong query_ca
     {
       BLOCK_LOCK_WR(block);
       Query_cache_query *query= block->query();
-      if (query && query->writer())
+      if (query->writer())
       {
         /*
            Drop the writer; this will cancel any attempts to store 
@@ -1146,7 +1146,7 @@ ulong Query_cache::resize(ulong query_ca
         query->writer(0);
         refused++;
       }
-      BLOCK_UNLOCK_WR(block);
+      query->unlock_n_destroy();
       block= block->next;
     } while (block != queries_blocks);
   }

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