CHESSConcurrencyTesting
Author: Jun Yan Ma (ma23@purdue.edu)
Project description: ProjectDescription.pdf
CHESS program containing pthread function hooks: chess.cpp.
CHESS tool: chesstool.cpp.
Finding Atomicity Violations (Part 2)
sample2.c has an atomicity violation bug and it will crash the program in a certain schedule.
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Compile the
sample2binary by giving ourchess.soshared object precedence:make eg source=sample2 -
Ensure that
chess.cpphas been built:make chess.so -
Compile the CHESS tool binary:
make chesstool
At last, we now have the CHESS tool binary chesstool. To check sample2 for atomicity violations, run the CHESS tool with the proper arguments: ./chesstool sample2
The CHESS tool will now execute the program by finding all synchronization points and writing them to a dotfile .tracksyncpts. After that, it will iterate over all of the synchronization points. If the program crashes during an execution, CHESS tool will make a note of it and continue to the next iteration.
After all iterations have been executed, a crash report will be printed at the end, detailing the synchronization points where execution has failed.
If no concurrency errors (atomicity violation in particular) are detected, a cookie is given. 😄
In-Depth Explanation of Implementation
Initialization of CHESS tool will write 0/0 into file .tracksyncpts. chess.cpp will read it and detect that this is the first execution and computes the total number of synchronization points of the program. For example, if sample2 has 49 synchronization points, at the end of this first execution, .tracksyncpts will contain 1/49. What this means is that we are at the 1st execution out of a total of 49 executions.
Further running sample2 using ./run.sh sample2 will read in from .tracksyncpts file and accordingly switch thread at the current Nth synchronization point. The current execution counter is increased at every thread switch.
The CHESS program is designed to reset the Nth execution back to 1 when it has reached its total number of executions.