Concurrent Bug Patterns and How to Test Them

pswlab.kaist.ac.kr/lab-orientation/concurrentbugpattern.ppt

 

1. Introduction

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There can be two different types of bug patterns: those that involve an error introduced when implementing a design pattern that solves the problem well, and those that involve an error introduced when implementing an antipattern.

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2.2 Code Assumed to Be Protected
- Nonatomic Operations Assumed to Be Atomic (atomic하다고 가정하였으나 실제 그렇지 못한 경우)
- Two-Stage Access Bug Pattern (Sequential flow 자체가 atomic하지 못한 경우)
- Wrong Lock or No Lock (lock/unlock 관계가 올바르지 못한 경우)
- Double-checked Locking (performance 향상을 위해서 double-checking방안을 사용하였으나 잠재적 오류가 있는 경우)

// Broken multithreaded version
// "Double-Checked Locking" idiom
class Foo {
    private Helper helper = null;
    public Helper getHelper() {
        if (helper == null) {
            synchronized(this) {
                if (helper == null) {
                    helper = new Helper();
                }
            }
        }
        return helper;
    }
 
    // other functions and members...
}

2.3 Interleaving Assumed Never to Occur
- The sleep() Bug Pattern (sleep에 의해서 interleaving을 determine할 수 있는 것은 아니다.)
- Losing a Notify Bug Pattern (notify이후 wait를 하는 경우가 발생할 수 있다.)
- Blocking or Dead Thread Bug Pattern
- A "Blocking" Critical Section Bug Pattern
- The Orphaned Thread Bug Pattern (master thread terminates abnormally....)

 

3. New Timing Heuristics for Finding Concurrent Bug Patterns
'ConTest'는 intercepting filter design pattern 방식으로 context switch에 대한 제어를 행할 수 있다.

 

4. Deducing Concurrent Bug Patterns from Design Pattern

 

5. Conclusion

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The introduction of bug taxonomies facilitated the search for new sequential program testing techniques. We hope that the concurrent bug pattern taxonomy will serve the same purpose for concurrent programs.

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