Model Checking Multithreaded Programs by Means of Reduced Models

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A Multi-Core Solver for Parity Games

We describe a parallel algorithm for solving parity games,\ud with applications in, e.g., modal mu-calculus model\ud checking with arbitrary alternations, and (branching) bisimulation\ud checking. The algorithm is based on Jurdzinski's Small Progress\ud Measures. Actually, this is a class of algorithms, depending on\ud a selection heuristics.\ud \ud Our algorithm operates lock-free, and mostly wait-free (except for\ud infrequent termination detection), and thus allows maximum\ud parallelism. Additionally, we conserve memory by avoiding storage\ud of predecessor edges for the parity graph through strictly\ud forward-looking heuristics.\ud \ud We evaluate our multi-core implementation's behaviour on parity games\ud obtained from mu-calculus model checking problems for a set of\ud communication protocols, randomly generated problem instances, and\ud parametric problem instances from the literature.\ud \u

Formalizing the Java Memory Model for multithreaded program correctness and optimization

technical reportStandardized language level support for threads is one of the most important features of Java. However, defining and understanding the Java Memory Model (JMM) has turned out to be a big challenge. Several models produced to date are not as easily comparable as first thought. Given the growing interest in multi- threaded Java programming, it is essential to have a sound framework that would allow formal specification and reasoning about the JMM. This paper presents the Uniform Memory Model (UMM), a formal memory model specification frame- work. With a flexible architecture, it can be easily configured to capture different shared memory semantics including both architectural and language level memory models. Based on guarded commands, UMM is integrated with a model checking utility, providing strong built-in support for formal verification and pro- gram analysis. A formal specification of the JMM following the semantics proposed by Manson and Pugh is presented in UMM. Systematic analysis has revealed interesting properties of the proposed semantics. In addition, several mistakes from the original specification have been uncovered

A Metric Encoding for Bounded Model Checking (extended version)

In Bounded Model Checking both the system model and the checked property are translated into a Boolean formula to be analyzed by a SAT-solver. We introduce a new encoding technique which is particularly optimized for managing quantitative future and past metric temporal operators, typically found in properties of hard real time systems. The encoding is simple and intuitive in principle, but it is made more complex by the presence, typical of the Bounded Model Checking technique, of backward and forward loops used to represent an ultimately periodic infinite domain by a finite structure. We report and comment on the new encoding technique and on an extensive set of experiments carried out to assess its feasibility and effectiveness

Automatic Functional Testing of GUIs

Functional testing of GUIs can be automated using a test oracle derived from the GUI’s specification and from a restricted set of randomised test data. As test data, a set of randomly distorted test objects seems to work well, especially starting as we do with a ‘perfect’ object and then distorting this more and more as the test progresses. The number of test cases needed seems to be much smaller than that reported in other random testing papers. More work is needed to see if the approach is generally applicable: if so, the test engineer can spend his time writing GUI specifications at a high level of abstraction, rather than hand-generating test cases

Program Model Checking: A Practitioner's Guide

Program model checking is a verification technology that uses state-space exploration to evaluate large numbers of potential program executions. Program model checking provides improved coverage over testing by systematically evaluating all possible test inputs and all possible interleavings of threads in a multithreaded system. Model-checking algorithms use several classes of optimizations to reduce the time and memory requirements for analysis, as well as heuristics for meaningful analysis of partial areas of the state space Our goal in this guidebook is to assemble, distill, and demonstrate emerging best practices for applying program model checking. We offer it as a starting point and introduction for those who want to apply model checking to software verification and validation. The guidebook will not discuss any specific tool in great detail, but we provide references for specific tools

Asymptotic Analysis of Plausible Tree Hash Modes for SHA-3

Discussions about the choice of a tree hash mode of operation for a standardization have recently been undertaken. It appears that a single tree mode cannot address adequately all possible uses and specifications of a system. In this paper, we review the tree modes which have been proposed, we discuss their problems and propose remedies. We make the reasonable assumption that communicating systems have different specifications and that software applications are of different types (securing stored content or live-streamed content). Finally, we propose new modes of operation that address the resource usage problem for the three most representative categories of devices and we analyse their asymptotic behavior

Statistics and runtime verification

The importance of correctness of systems is becoming more crucial as computers control more of our everyday activities. Various approaches have been advocated and used for the verification of such correctness, with one of the more promising ones being runtime verification. One important issue in runtime verification is the logic used to specify properties, since this influences both the overheads induced by the monitors, and the applicability of the approach to a particular domain. In this paper we propose techniques for the expression and runtime monitoring of statistical properties, enabling easier manipulation and expression of non-functional requirements. The logic is developed as an extension of the existing runtime verification tool LARVA, and has been applied to an ftp server implementation, adding a new layer of probabilistic intrusion detection and system profiling.peer-reviewe