This is the CM-IOCov repository, which is an extension of CrashMonkey with improved input coverage. The paper of CM-IOCov and input/output testing for file systems is published in ACM SYSTOR 2025, and the PDF version is here.

CM-IOCov has a dedicated input driver to generate inputs (file system call arguments) and does not use the original way of CrashMonkey selecting inputs, to support diverse inputs for generating test workloads. CM-IOCov reuses all other parts of CrashMonkey for crash consistency bug detection such as crash generation, oracle generation, and auto checker. For more information about CrashMonkey, please refer to the CrashMonkey README and paper.

This repository is cloned from the original CrashMonkey repo and makes changes to support CM-IOCov. For the master branch here, the implementation is still the original CrashMonkey, please see the Branches for implementations of CM-IOCov.

The associated repository with CM-IOCov is IOCov (https://github.com/sbu-fsl/IOCov), which measures input and output coverage for file system testing tools.

This repository provides multiple branches to distinguish between the original CrashMonkey and CM-IOCov, as well as kernel version support:

• master
  The original CrashMonkey codebase without CM-IOCov modifications. CrashMonkey supports Linux kernels up to 5.6.

• cmiocov-base
  Baseline CM-IOCov branch built on top of CrashMonkey, supporting the same kernel versions as the original CrashMonkey (up to Linux 5.6).

• crashmonkey-linux-6.12
  CrashMonkey adapted to support Linux kernel 6.12, extending kernel compatibility beyond 5.6.

• cm-iocov-linux-6.12
  CM-IOCov adapted to support Linux kernel 6.12, with extended input coverage functionality in addition to the newer kernel support.

The usage of CM-IOCov is identical to CrashMonkey. Please follow the instructions in the CrashMonkey README. First, check out the respective branch that matches your kernel version (cmiocov-base for kernels up to 5.6, cm-iocov-linux-6.12 for Linux 6.12). Then build the tests and run them using the same workflow as CrashMonkey to execute workloads and check for crash consistency bugs.

@INPROCEEDINGS{systor25cmiocov,
  TITLE =        "Enhanced File System Testing through Input and Output Coverage",
  AUTHOR =       "Yifei Liu and Geoff Kuenning and Md. Kamal Parvez and Scott Smolka and Erez Zadok",
  BOOKTITLE =    "Proceedings of the 18th ACM International Systems and Storage Conference (SYSTOR '25)",
  ADDRESS =      "Virtual Event",
  MONTH =        "September",
  YEAR =         "2025",
  PUBLISHER =    "ACM",
}

For any question, please feel free to contact Yifei Liu (yifeliu@cs.stonybrook.edu) and Erez Zadok (ezk@cs.stonybrook.edu). Alternatively, you can create an issue in this repository.