A Bug’s Life (ABL) Julia Lawall (Inria/LIP6-Regal) Gilles Muller (Inria/LIP6-Regal)

A Bug’s Life (ABL)
Julia Lawall (Inria/LIP6-Regal)
Gilles Muller (Inria/LIP6-Regal)

Software has bugs!
Our target: Large, open-source infrastructure software
•Low-level, multifunctional code
•Widely dispersed developers
•Examples: The Linux kernel, the Python runtime, etc.
Challenges:
•What code is fault prone?
•How to find faults?

What code is fault prone?
Case study: The Linux kernel.
Prior hypotheses:
•Linux is large, growing, and full of faults.
•Device drivers are of low quality.
•Results of Chou et al. [SOSP 2001]

Results: Code size
1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
0
2
4
6
8Other
Drivers/Staging
Arch
Drivers w/o Staging
File Systems (FS)
Net
Sound
1.0
1.2.0
2.0
2.1.0
2.2.0
2.3.0
2.4.0
2.4.1
2.5.0
2.6.0
2.6.12
2.6.28

Results: Fault rate
2004 2005 2006 2007 2008 2009 2010
0.0
0.2
0.4
0.6
0.8
% of faulty notes
Average
Staging
Drivers
Sound
Arch
FS
Net
Other