1---
2layout: default
3title: ClusterFuzz
4parent: Further reading
5nav_order: 1
6permalink: /further-reading/clusterfuzz/
7---
8
9# ClusterFuzz
10
11[ClusterFuzz](https://github.com/google/clusterfuzz) is the distributed fuzzing
12infrastructure behind OSS-Fuzz. It was initially built for fuzzing Chrome at
13scale.
14
15- TOC
16{:toc}
17---
18
19## Web interface
20
21ClusterFuzz provides a [web interface](https://oss-fuzz.com)
22to view statistics about your fuzz targets, as well as current crashes.
23
24*Note*: Access is restricted to project developers who we auto CC on new bug
25reports.
26
27## Testcase reports
28
29ClusterFuzz will automatically de-duplicate and file reproducible crashes into
30our [bug tracker](https://bugs.chromium.org/p/oss-fuzz/issues/list). We provide
31a crash report page that gives you the stack trace, a link to the crashing
32testcase, and regression ranges where the bug was most likely introduced.
33
34![report]({{ site.baseurl }}/images/pcre2_testcase.png?raw=true)
35
36## Fuzzer stats
37
38You can view statistics about your fuzz targets (e.g. speed, coverage
39information, memory usage) on our fuzzer statistics dashboard.
40
41![stats]({{ site.baseurl }}/images/freetype_stats_graphs.png?raw=true)
42
43![stats]({{ site.baseurl }}/images/freetype_stats_table.png?raw=true)
44
45## Coverage reports
46
47We provide coverage reports, where we highlight the parts of source code that
48are being reached by your fuzz target. Make sure to look at the uncovered code
49marked in red and add appropriate fuzz targets to cover those usecases.
50
51![coverage_1]({{ site.baseurl }}/images/freetype_coverage_1.png?raw=true)
52![coverage_2]({{ site.baseurl }}/images/freetype_coverage_2.png?raw=true)
53
54## Performance analyzer
55
56You can view performance issues that your fuzz target is running into (e.g.
57leaks, timeouts, etc) by clicking on `Performance` link on our fuzzer statistics
58dashboard. Make sure to fix all cited issues, so as to keep your fuzz target
59running efficiently and finding new bugs.
60
61![performance_analyzer]({{ site.baseurl }}/images/expat_performance_analyzer.png?raw=true)
62
63## Crash stats
64
65You can view statistics of crashes over time on our crash statistics dashboard.
66
67![crash_stats]({{ site.baseurl }}/images/crash_stats.png?raw=true)
68