The process scheduler in the Linux kernel 2.4 performs scheduling based on CPU billing gathered from periodic process sampling ticks, which allows local users to cause a denial of service (CPU consumption) by performing voluntary nanosecond sleeps that result in the process not being active during a clock interrupt, as described in "Secretly Monopolizing the CPU Without Superuser Privileges."

References

• https://nvd.nist.gov/vuln/detail/CVE-2007-3720
• http://osvdb.org/37126
• http://www.cs.huji.ac.il/~dants/papers/Cheat07Security.pdf