Publications by Cristian Zamfir

Automatic generation of program execution that reaches a given failure point

An execution of a target software program that causes a particular bug to manifest itself is generated. A target software program is received. A bug report generated by an execution of the target software program is received. The bug report describes a par ...

2015

Automated Classification of Data Races Under Both Strong and Weak Memory Models

George Candea, Cristian Zamfir, Baris Can Cengiz Kasikci

Data races are one of the main causes of concurrency problems in multithreaded programs. Whether all data races are bad, or some are harmful and others are harmless, is still the subject of vigorous scientific debate [Narayanasamy et al. 2007; Boehm 2012]. ...

Assoc Computing Machinery2015

Parallel symbolic execution on cluster of commodity hardware

George Candea, Cristian Zamfir, Stefan Bucur

A symbolic execution task is dynamically divided among multiple computing nodes. Each of the multiple computing nodes explores a different portion of a same symbolic execution tree independently of other computing nodes. Workload status updates are receive ...

2014

Automated Debugging for Arbitrarily Long Executions

George Candea, Cristian Zamfir, Baris Can Cengiz Kasikci, Johannes Kinder, Edouard Bugnion

One of the most energy-draining and frustrating parts of software development is playing detective with elusive bugs. In this paper we argue that automated post-mortem debugging of failures is feasible for real, in-production systems with no runtime record ...

2013

Execution Synthesis: A Technique for Automating the Debugging of Software

Cristian Zamfir

Debugging real systems is hard, requires deep knowledge of the target code, and is time-consuming. Bug reports rarely provide sufficient information for debugging, thus forcing developers to turn into detectives searching for an explanation of how the prog ...

EPFL2013

Data Races vs. Data Race Bugs: Telling the Difference with Portend

George Candea, Cristian Zamfir, Baris Can Cengiz Kasikci

Even though most data races are harmless, the harmful ones are at the heart of some of the worst concurrency bugs. Alas, spotting just the harmful data races in programs is like finding a needle in a haystack: 76%-90% of the true data races reported by sta ...

Acm Order Department, P O Box 64145, Baltimore, Md 21264 Usa2012

CoRD: A Collaborative Framework for Distributed Data Race Detection

George Candea, Cristian Zamfir, Baris Can Cengiz Kasikci

Modern concurrent software is riddled with data races and these races constitute the source of many problems. Data races are hard to detect accurately before software is shipped and, once they cause failures in production, developers find it challenging to ...

Usenix2012

Debug Determinism: The Sweet Spot for Replay-Based Debugging

George Candea, Cristian Zamfir

Deterministic replay tools offer a compelling approach to debugging hard-to-reproduce bugs. Recent work on relaxed-deterministic replay techniques shows that replay debugging with low in-production overhead is possible. However, despite considerable progre ...

2011

Parallel symbolic execution for automated real-world software testing

George Candea, Cristian Zamfir, Stefan Bucur, Vlad Ureche

This paper introduces Cloud9, a platform for automated testing of real-world software. Our main contribution is the scalable parallelization of symbolic execution on clusters of commodity hardware, to help cope with path explosion. Cloud9 provides a system ...

ACM Press2011

Execution Synthesis: A Technique for Automated Software Debugging

George Candea, Cristian Zamfir

Debugging real systems is hard, requires deep knowledge of the code, and is time-consuming. Bug reports rarely provide sufficient information, thus forcing developers to turn into detectives searching for an explanation of how the program could have arrive ...

2010

Automated Software Testing as a Service (TaaS)

George Candea, Cristian Zamfir, Stefan Bucur

This paper makes the case for TaaS - automated software testing as a cloud-based service. We present three kinds of TaaS: (1) a public certification service, akin to Underwriters Labs, that independently assesses the reliability, safety, and security of so ...

2010

Selective Symbolic Execution

Vitaly Chipounov, George Candea, Cristian Zamfir

Symbolic execution is a powerful technique for analyzing program behavior, finding bugs, and generating tests, but suffers from severely limited scalability: the largest programs that can be symbolically executed today are on the order of thousands of line ...

2009

Deadlock Immunity: Enabling Systems To Defend Against Deadlocks

Daniel Tralamazza, George Candea, Horatiu Jula, Cristian Zamfir

Deadlock immunity is a property by which programs, once afflicted by a given deadlock, develop resistance against future occurrences of that and similar deadlocks. We describe a technique that enables programs to automatically gain such immunity without as ...

2008