Bug#11757464:SERVER CRASH IN RECURSIVE CALL WHEN OOM

Analysis:
---------

When the server is out of memory, an error is raised
to indicate the same. Handling the error requires
more memory to be allocated which fails, hence the
error handling loops in a recursion and causes the
server to crash.

Fix:
---
a) Prevents pushing the 'out of memory' error condition
to the diagnostic area as it requires memory allocation.
GET DIAGNOSTICS, SHOW WARNINGS and SHOW ERRORS statements
will not show information about this error. However the
'out of memory' error is returned to the client.
b) It sets the ME_FATALERROR flag when 'out of memory' errors
are reported (for places where the flag is not already set).
This flag prevents activation of SP error handlers which also
require memory allocation and therefore are likely to fail.

Author: Nisha Gopalakrishnan

mysys/mf_keycache.c

@@ -444,7 +444,8 @@ int init_key_cache(KEY_CACHE *keycache, uint key_cache_block_size,
       if (blocks < 8)
       {
         my_errno= ENOMEM;
-        my_error(EE_OUTOFMEMORY, MYF(0), blocks * keycache->key_cache_block_size);
+        my_error(EE_OUTOFMEMORY, MYF(ME_FATALERROR),
+                 blocks * keycache->key_cache_block_size);
         goto err;
       }
       blocks= blocks / 4*3;

mysys/my_lockmem.c

@@ -43,7 +43,7 @@ uchar *my_malloc_lock(uint size,myf MyFlags)
   if (!(ptr=memalign(pagesize,size)))
   {
     if (MyFlags & (MY_FAE+MY_WME))
-      my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG),size);
+      my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG+ME_FATALERROR), size);
     DBUG_RETURN(0);
   }
   success = mlock((uchar*) ptr,size);

mysys/my_malloc.c

@@ -41,14 +41,20 @@ void *my_malloc(size_t size, myf my_flags)
                     free(point);
                     point= NULL;
                   });
+  DBUG_EXECUTE_IF("simulate_persistent_out_of_memory",
+                  {
+                    free(point);
+                    point= NULL;
+                  });
 
   if (point == NULL)
   {
     my_errno=errno;
     if (my_flags & MY_FAE)
       error_handler_hook=fatal_error_handler_hook;
     if (my_flags & (MY_FAE+MY_WME))
-      my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG+ME_NOREFRESH),size);
+      my_error(EE_OUTOFMEMORY, MYF(ME_BELL + ME_WAITTANG +
+                                   ME_NOREFRESH + ME_FATALERROR),size);
     DBUG_EXECUTE_IF("simulate_out_of_memory",
                     DBUG_SET("-d,simulate_out_of_memory"););
     if (my_flags & MY_FAE)
@@ -90,7 +96,7 @@ void *my_realloc(void *oldpoint, size_t size, myf my_flags)
       DBUG_RETURN(oldpoint);
     my_errno=errno;
     if (my_flags & MY_FAE+MY_WME)
-      my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG),size);
+      my_error(EE_OUTOFMEMORY, MYF(ME_BELL + ME_WAITTANG + ME_FATALERROR),size);
   }
   else
   {
@@ -106,7 +112,7 @@ void *my_realloc(void *oldpoint, size_t size, myf my_flags)
       DBUG_RETURN(oldpoint);
     my_errno=errno;
     if (my_flags & (MY_FAE+MY_WME))
-      my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG), size);
+      my_error(EE_OUTOFMEMORY, MYF(ME_BELL + ME_WAITTANG + ME_FATALERROR), size);
   }
 #endif
   DBUG_PRINT("exit",("ptr: %p", point));

mysys/my_once.c

@@ -59,7 +59,7 @@ void* my_once_alloc(size_t Size, myf MyFlags)
     {
       my_errno=errno;
       if (MyFlags & (MY_FAE+MY_WME))
-	my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG),get_size);
+	my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_WAITTANG+ME_FATALERROR), get_size);
       return((uchar*) 0);
     }
     DBUG_PRINT("test",("my_once_malloc %lu byte malloced", (ulong) get_size));

sql/handler.cc

@@ -356,7 +356,8 @@ handler *get_ha_partition(partition_info *part_info)
   }
   else
   {
-    my_error(ER_OUTOFMEMORY, MYF(0), static_cast<int>(sizeof(ha_partition)));
+    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), 
+             static_cast<int>(sizeof(ha_partition)));
   }
   DBUG_RETURN(((handler*) partition));
 }

sql/item_sum.cc

@@ -3211,8 +3211,12 @@ bool Item_func_group_concat::add()
   TREE_ELEMENT *el= 0;                          // Only for safety
   if (row_eligible && tree)
   {
+    DBUG_EXECUTE_IF("trigger_OOM_in_gconcat_add",
+                     DBUG_SET("+d,simulate_persistent_out_of_memory"););
     el= tree_insert(tree, table->record[0] + table->s->null_bytes, 0,
                     tree->custom_arg);
+    DBUG_EXECUTE_IF("trigger_OOM_in_gconcat_add",
+                    DBUG_SET("-d,simulate_persistent_out_of_memory"););
     /* check if there was enough memory to insert the row */
     if (!el)
       return 1;

sql/sql_binlog.cc

@@ -107,7 +107,7 @@ void mysql_client_binlog_statement(THD* thd)
         rli->relay_log.description_event_for_exec &&
         buf))
   {
-    my_error(ER_OUTOFMEMORY, MYF(0), 1);  /* needed 1 bytes */
+    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), 1);  /* needed 1 bytes */
     goto end;
   }
 

sql/sql_class.cc

@@ -1136,10 +1136,14 @@ MYSQL_ERROR* THD::raise_condition(uint sql_errno,
 
   query_cache_abort(&query_cache_tls);
 
-  /* When simulating OOM, skip writing to error log to avoid mtr errors */
-  DBUG_EXECUTE_IF("simulate_out_of_memory", DBUG_RETURN(NULL););
-
-  cond= warning_info->push_warning(this, sql_errno, sqlstate, level, msg);
+  /* 
+     Avoid pushing a condition for out of memory errors as this will require
+     memory allocation and therefore might fail.
+  */
+  if (sql_errno != EE_OUTOFMEMORY && sql_errno != ER_OUTOFMEMORY)
+  {
+    cond= warning_info->push_warning(this, sql_errno, sqlstate, level, msg);
+  }
   DBUG_RETURN(cond);
 }
 
@@ -1938,7 +1942,7 @@ CHANGED_TABLE_LIST* THD::changed_table_dup(const char *key, long key_length)
 				      key_length + 1);
   if (!new_table)
   {
-    my_error(EE_OUTOFMEMORY, MYF(ME_BELL),
+    my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_FATALERROR),
              ALIGN_SIZE(sizeof(TABLE_LIST)) + key_length + 1);
     killed= KILL_CONNECTION;
     return 0;
@@ -2493,7 +2497,7 @@ bool select_export::send_data(List<Item> &items)
       set_if_smaller(estimated_bytes, UINT_MAX32);
       if (cvt_str.realloc((uint32) estimated_bytes))
       {
-        my_error(ER_OUTOFMEMORY, MYF(0), (uint32) estimated_bytes);
+        my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), (uint32) estimated_bytes);
         goto err;
       }
 

sql/sql_partition.cc

@@ -7044,7 +7044,8 @@ void set_key_field_ptr(KEY *key_info, const uchar *new_buf,
 
 void mem_alloc_error(size_t size)
 {
-  my_error(ER_OUTOFMEMORY, MYF(0), static_cast<int>(size));
+  my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), 
+           static_cast<int>(size));
 }
 
 #ifdef WITH_PARTITION_STORAGE_ENGINE

sql/sql_prepare.cc

@@ -1475,7 +1475,8 @@ static int mysql_test_select(Prepared_statement *stmt,
 
   if (!lex->result && !(lex->result= new (stmt->mem_root) select_send))
   {
-    my_error(ER_OUTOFMEMORY, MYF(0), static_cast<int>(sizeof(select_send)));
+    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), 
+             static_cast<int>(sizeof(select_send)));
     goto error;
   }
 
@@ -1842,7 +1843,7 @@ static bool mysql_test_multidelete(Prepared_statement *stmt,
   stmt->thd->lex->current_select= &stmt->thd->lex->select_lex;
   if (add_item_to_list(stmt->thd, new Item_null()))
   {
-    my_error(ER_OUTOFMEMORY, MYF(0), 0);
+    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), 0);
     goto error;
   }
 
@@ -3755,7 +3756,7 @@ bool Prepared_statement::execute(String *expanded_query, bool open_cursor)
       alloc_query(thd, (char*) expanded_query->ptr(),
                   expanded_query->length()))
   {
-    my_error(ER_OUTOFMEMORY, 0, expanded_query->length());
+    my_error(ER_OUTOFMEMORY, MYF(ME_FATALERROR), expanded_query->length());
     goto error;
   }
   /*

sql/sql_select.cc

@@ -14417,7 +14417,7 @@ static int remove_dup_with_compare(THD *thd, TABLE *table, Field **first_field,
     }
     if (copy_blobs(first_field))
     {
-      my_message(ER_OUTOFMEMORY, ER(ER_OUTOFMEMORY), MYF(0));
+      my_message(ER_OUTOFMEMORY, ER(ER_OUTOFMEMORY), MYF(ME_FATALERROR));
       error=0;
       goto err;
     }

storage/myisam/myisampack.c

@@ -2151,7 +2151,8 @@ static my_off_t write_huff_tree(HUFF_TREE *huff_tree, uint trees)
   */
   if (!(packed_tree=(uint*) my_alloca(sizeof(uint)*length*2)))
   {
-    my_error(EE_OUTOFMEMORY,MYF(ME_BELL),sizeof(uint)*length*2);
+    my_error(EE_OUTOFMEMORY, MYF(ME_BELL+ME_FATALERROR), 
+             sizeof(uint)*length*2);
     return 0;
   }