github.com/google/syzkaller@v0.0.0-20240517125934-c0f1611a36d6/docs/troubleshooting.md (about)

     1  # Troubleshooting
     2  
     3  Here are some things to check if there are problems running syzkaller.
     4  
     5   - Use the `-debug` command line option to make syzkaller print all possible debug output,
     6     from both the `syz-manager` top-level program and the `syz-fuzzer` instances. With this option
     7     syzkaller will only run one VM instance.
     8  
     9   - Use the `-vv N` command line option to increase the amount of logging output, from both
    10     the `syz-manager` top-level program and the `syz-fuzzer` instances (which go to the
    11     output files in the `crashes` subdirectory of the working directory). Higher values of
    12     N give more output.
    13  
    14   - If logging indicates problems with the executor program (e.g. `executor failure`),
    15     try manually running a short sequence of system calls:
    16       - Copy `syz-executor` and `syz-execprog` into a running VM.
    17       - In the VM run `./syz-execprog -executor ./syz-executor -debug sampleprog` where
    18         sampleprog is a simple system call script (e.g. just containing `getpid()`).
    19       - For example, if this reports that `clone` has failed, this probably indicates
    20         that the test kernel does not include support for all of the required namespaces.
    21         In this case, running the `syz-execprog` test with the `-sandbox=setuid` option fixes the problem,
    22         so the main configuration needs to be updated to set `sandbox` to `setuid`.
    23  
    24   - If syzkaller prinths the `failed to copy binary` error shortly after VM has booted:
    25       - If you're using Buildroot images and the error output contains the `subsystem request
    26         failed on channel 0` line, this can be due to the [OpenSSH 9.0 changes](https://www.openssh.com/txt/release-9.0)
    27         that force the use of the SFTP protocol. Upgrade your Buildroot image to the latest version and
    28         make sure SFTP is enabled there.
    29  
    30  Also see [this](linux/troubleshooting.md) for Linux kernel specific troubleshooting advice.
    31  
    32  If none of the above helps, file a bug on [the bug tracker](https://github.com/google/syzkaller/issues)
    33  or ask us directly on the syzkaller@googlegroups.com mailing list.
    34  Please include syzkaller commit id that you use and `syz-manager` output with `-debug` flag enabled if applicable.