Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userSthread: In-Vivo Model Checking of Multithreaded Programs
190
0
0.0
(
0
)
Added by
Gene Cooperman
Publication date
2020
fields
Informatics Engineering
and research's language is
English
Ask ChatGPT about the research
No Arabic abstract
This work strives to make formal verification of POSIX multithreaded programs easily accessible to general programmers. Sthread operates directly on multithreaded C/C++ programs, without the need for an intermediate formal model. Sthread is in-vivo in that it provides a drop-in replacement for the pthread library, and operates directly on the compiled target executable and application libraries. There is no compiler-generated intermediate representation. The system calls in the application remain unaltered. Optionally, the programmer can add a small amount of additional native C code to include assertions based on the users algorithm, declarations of shared memory regions, and progress/liveness conditions. The work has two important motivations: (i) It can be used to verify correctness of a concurrent algorithm being implemented with multithreading; and (ii) it can also be used pedagogically to provide immediate feedback to students learning either to employ POSIX threads system calls or to implement multithreaded algorithms. This work represents the first example of in-vivo model checking operating directly on the standard multithreaded executable and its libraries, without the aid of a compiler-generated intermediate representation. Sthread leverages the open-source SimGrid libraries, and will eventually be integrated into SimGrid. Sthread employs a non-preemptive model in which thread context switches occur only at multithreaded system calls (e.g., mutex, semaphore) or before accesses to shared memory regions. The emphasis is on finding algorithmic bugs (bugs in an original algorithm, implemented as POSIX threads and shared memory regions. This work is in contrast to Context-Bounded Analysis (CBA), which assumes a preemptive model for threads, and emphasizes implementation bugs such as buffer overruns and write-after-free for memory allocation. In particular, the Sthread in-vivo approach has strong future potential for pedagogy, by providing immediate feedback to students who are first learning the correct use of Pthreads system calls in implementation of concurrent algorithms based on multithreading.
rate research
Read More
In this paper we investigate the applicability of standard model checking approaches to verifying properties in probabilistic programming. As the operational model for a standard probabilistic program is a potentially infinite parametric Markov decision process, no direct adaption of existing techniques is possible. Therefore, we propose an on-the-fly approach where the operational model is successively created and verified via a step-wise execution of the program. This approach enables to take key features of many probabilistic programs into account: nondeterminism and conditioning. We discuss the restrictions and demonstrate the scalability on several benchmarks.
In this article, we give an overview of our project on higher-order program verification based on HFL (higher-order fixpoint logic) model checking. After a brief introduction to HFL, we explain how it can be applied to program verification, and summarize the current status of the project.
This paper presents a program logic for reasoning about multithreaded Java-like programs with dynamic thread creation, thread joining and reentrant object monitors. The logic is based on concurrent separation logic. It is the first detailed adaptation of concurrent separation logic to a multithreaded Java-like language. The program logic associates a unique static access permission with each heap location, ensuring exclusive write accesses and ruling out data races. Concurrent reads are supported through fractional permissions. Permissions can be transferred between threads upon thread starting, thread joining, initial monitor entrancies and final monitor exits. In order to distinguish between initial monitor entrancies and monitor reentrancies, auxiliary variables keep track of multisets of currently held monitors. Data abstraction and behavioral subtyping are facilitated through abstract predicates, which are also used to represent monitor invariants, preconditions for thread starting and postconditions for thread joining. Value-parametrized types allow to conveniently capture common strong global invariants, like static object ownership relations. The program logic is presented for a model language with Java-like classes and interfaces, the soundness of the program logic is proven, and a number of illustrative examples are presented.
We introduce a transformation system for concurrent constraint programming (CCP). We define suitable applicability conditions for the transformations which guarantee that the input/output CCP semantics is preserved also when distinguishing deadlocked computations from successful ones and when considering intermediate results of (possibly) non-terminating computations. The system allows us to optimize CCP programs while preserving their intended meaning: In addition to the usual benefits that one has for sequential declarative languages, the transformation of concurrent programs can also lead to the elimination of communication channels and of synchronization points, to the transformation of non-deterministic computations into deterministic ones, and to the crucial saving of computational space. Furthermore, since the transformation system preserves the deadlock behavior of programs, it can be used for proving deadlock freeness of a given program wrt a class of queries. To this aim it is sometimes sufficient to apply our transformations and to specialize the resulting program wrt the given queries in such a way that the obtained program is trivially deadlock free.
We extend a technique called Compiling Control. The technique transforms coroutining logic programs into logic programs that, when executed under the standard left-to-right selection rule (and not using any delay features) have the same computational behavior as the coroutining program. In recent work, we revised Compiling Control and reformulated it as an instance of Abstract Conjunctive Partial Deduction. This work was mostly focused on the program analysis performed in Compiling Control. In the current paper, we focus on the synthesis of the transformed program. Instead of synthesizing a new logic program, we synthesize a CHR(Prolog) program which mimics the coroutining program. The synthesis to CHR yields programs containing only simplification rules, which are particularly amenable to certain static analysis techniques. The programs are also more concise and readable and can be ported to CHR implementations embedded in other languages than Prolog.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
