Runtime prevention of concurrency related type-state violations in multithreaded applications

Abstract

We propose a new method for runtime prevention of type state violations in multithreaded applications due to erroneous thread interleavings. The new method employs a combination of static and dynamic program analysis techniques to control the execution order of the method calls to suppress illegal call sequences. The legal behavior of a shared object is specified by a type-state automaton, which serves as the guidance for our method to delay certain method calls at run time. Our main contribution is a new theoretical framework for ensuring that the runtime prevention strategy is always safe, i.e., they do not introduce new erroneous interleavings. Furthermore, whenever the static program analysis is precise enough, our method guarantees to steer the program to a failurefree interleaving as long as such interleaving exists. We have implemented the new method in a tool based on the LLVM compiler framework. Our experiments on a set of multithreaded C/C++ applications show that the method is both efficient and effective in suppressing concurrency related type-state violations.

Lightweight verification via specialized typecheckers

“…A key barrier to sound typestate analyses is the need to reason about aliasing. Consider the classic example [137,325,287,129,138,302,320,275,324,318,6,243,80,184,10,75,328,101,102] of a File object, whose typestate is specified in fig. 3.1, and the following program in a Java-like imperative language: File f = new File(...); f.open(); File g = f; // f and g are aliases after this line is executed g.close(); f.read(); // an error occurs when this line is executed On line 3, the shared object-which both aliases f and g refer to-is in the open typestate.…”

“…The need to call a distinguished initialization method on an object after its constructor finishes but before using it appears 7 times across 4 papers [123,81,275,324]. For example, when using a Socket object, one must call connect() before using it to send data (fig.…”

Shield Synthesis for Real: Enforcing Safety in Cyber-Physical Systems

“…Runtime enforcement is related to, but also different from, the various software techniques for error avoidance. For example, failure-oblivious computing [25], [38] was used to allow software applications to execute through memory errors; temporal properties [26], [46] were leveraged to control thread schedules to avoid runtime failures of concurrent software. However, these techniques are not designed to target cyberphysical systems with real-valued signals, where corrections are expected to be made instantaneously, i.e., in the same time step when errors occur.…”

Development of Technique for Healing Data Races based on Software Transactional Memory

“…Thus, recent works have being introduced the techniques of healing data races rather than detecting the bugs. Existing techniques that heal data races [7][8][9][10][11] can be categorized into three approaches: always-on, failure-recovery, and post-mortem. Always-on approach constrains program execution all the time to prevent potential manifestations of some concurrency bugs [10].…”