How to use syzkaller


Start the syz-manager process as:

./bin/syz-manager -config my.cfg

The syz-manager process will wind up VMs and start fuzzing in them. The -config command line option gives the location of the configuration file, which is described here. Found crashes, statistics and other information is exposed on the HTTP address specified in the manager config.


Once syzkaller detected a kernel crash in one of the VMs, it will automatically start the process of reproducing this crash (unless you specified "reproduce": false in the config). By default it will use 4 VMs to reproduce the crash and then minimize the program that caused it. This may stop the fuzzing, since all of the VMs might be busy reproducing detected crashes.

The process of reproducing one crash may take from a few minutes up to an hour depending on whether the crash is easily reproducible or reproducible at all. Since this process is not perfect, there's a way to try to manually reproduce the crash, as described here.

If a reproducer is successfully found, it can be generated in one of the two forms: syzkaller program or C program. Syzkaller always tries to generate a more user-friendly C reproducer, but sometimes fails for various reasons (for example slightly different timings). In case syzkaller only generated a syzkaller program, there's a way to execute them to reproduce and debug the crash manually.

Reporting bugs

Check here for the instructions on how to report Linux kernel bugs.


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