Table 31.1: Bugs In Modern Applications

Researchers have spent a great deal of time and effort looking into concurrency bugs over many years. Much of the early work fo-cused on deadlock, a topic which we’ve touched on in the past chap-ters but will now dive into deeply [C+71]. More recent work fo-cuses on studying other types of common concurrency bugs (i.e., non-deadlock bugs). In this chapter, we take a brief look at some example concurrency problems found in real code bases, to better understand what problems to look out for. And thus our problem: CRUX: HOW TO HANDLE COMMON CONCURRENCY BUGS Concurrency bugs tend to come in a variety of common patterns. Knowing which ones to look out for is the first step to writing more robust, correct concurrent code. 31.1 What Types Of Bugs Exist? The first, andmost obvious, question is this: what types of concur-rency bugs manifest in complex, concurrent programs? This ques-tion is difficult to answer in general, but fortunately, some others have done the work for us. Specifically, we rely upon a study by Lu et al. [L+08], which analyzes a number of popular concurrent ap-plications in great detail to understand what types of bugs arise in practice.