Utah Verifier Group Research Overview Robert Palmer

Modeling MPI Find Deadlocks Guarantee Assertions Optimize Correctly a b b a \/ /\ pc=1 /\a /\ pc’=2 \/ /\ pc=1 /\b /\ pc’=3 \/ /\ pc=2 /\b /\ pc’=1 \/ /\ pc=3 /\a /\ pc’=1 (Robert Palmer)

Verification of MPI one-sided communication MPI one-sided communication –Implementation of shared memory in a message passing paradigm. –A process can make its memory space available for use by other processes. –Other processes can read/write from this memory space without explicit communication with the owner Case Study: Byte-range-locks using MPI one-sided –One-sided uses a relaxed memory model which makes locking harder –Model checking can be used to detect deadlocks/livelocks in locking algorithms –Traditional testing not enough to uncover serious bugs (Salman Pervez)

Control Flow Model Extraction from Visual Studio Uses VS Extensibility classes to extract code elements Each function is analyzed with a parse engine (Gold Parser) and fed a grammar, producing a parse tree The parse tree is used to generate a control flow graph (Geof Sawaya)

Verifying Hierarchical Cache Coherence Protocols Design a prototype protocol –Build and verify each level of the hierarchy protocol separately –Combine all level protocols into the full protocol afterwards Verify the hierarchical protocol –Use various abstractions –Use assume-guarantee reasoning (Xiaofang Chen)

Under-approximation Model Checking for Concurrent Programs Testing Concurrent C Programs is still hard –Difficult to instrument the binary code –Don’t have infrastructure like JavaPathfinder whichprovides forward/roll- back for program execution Our Method –Use external scheduler to control the program execution –Restart from beginning and choose a new interleaving trace scheduler request /reply Instrumented multithreaded program Instrumented multithreaded program Instrumented multithreaded program request /reply (Yu Yang)