CWE-585 空的同步代码块

Empty Synchronized Block

结构: Simple

Abstraction: Variant

状态: Draft

被利用可能性: unkown

基本描述

The software contains an empty synchronized block.

扩展描述

An empty synchronized block does not actually accomplish any synchronization and may indicate a troubled section of code. An empty synchronized block can occur because code no longer needed within the synchronized block is commented out without removing the synchronized block.

相关缺陷

• cwe_Nature: ChildOf cwe_CWE_ID: 1071 cwe_View_ID: 1000 cwe_Ordinal: Primary

• cwe_Nature: ChildOf cwe_CWE_ID: 1071 cwe_View_ID: 699 cwe_Ordinal: Primary

适用平台

Language: {'cwe_Name': 'Java', 'cwe_Prevalence': 'Undetermined'}

常见的影响

范围	影响	注释
Other	Other	An empty synchronized block will wait until nobody else is using the synchronizer being specified. While this may be part of the desired behavior, because you haven't protected the subsequent code by placing it inside the synchronized block, nothing is stopping somebody else from modifying whatever it was you were waiting for while you run the subsequent code.

可能的缓解方案

Implementation

策略:

When you come across an empty synchronized statement, or a synchronized statement in which the code has been commented out, try to determine what the original intentions were and whether or not the synchronized block is still necessary.

示例代码

例

The following code attempts to synchronize on an object, but does not execute anything in the synchronized block. This does not actually accomplish anything and may be a sign that a programmer is wrestling with synchronization but has not yet achieved the result they intend.

bad Java

Instead, in a correct usage, the synchronized statement should contain procedures that access or modify data that is exposed to multiple threads. For example, consider a scenario in which several threads are accessing student records at the same time. The method which sets the student ID to a new value will need to make sure that nobody else is accessing this data at the same time and will require synchronization.

good

分类映射

映射的分类名	ImNode ID	Fit	Mapped Node Name
Software Fault Patterns	SFP21		Multiple locks/unlocks

引用

• REF-478 Intrinsic Locks and Synchronization (in Java)

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