Example

Example of a segmentation fault on Linux:

$ python
>>> import faulthandler
>>> faulthandler.isenabled()
True
>>> faulthandler.sigsegv()
Fatal Python error: Segmentation fault

Traceback (most recent call first):
  File "<stdin>", line 1 in <module>
Segmentation fault

Installation

To install faulthandler module, type the following command:

python setup.py install

Then you can test your setup using the following command:

python tests.py

You need a C compiler (eg. gcc) and Python headers to build the faulthandler module. Eg. on Fedora, you have to install python-devel package (sudo yum install python-devel).

faulthandler module API

Fault handler state:

• enable(): enable the fault handler (it is enabled by default)
• disable(): disable the fault handler
• isenabled(): get the status of the fault handler

Functions to test the fault handler:

• sigbus(): raise a SIGBUS signal (Bus error)
• sigfpe(): raise a SIGFPE signal (Floating point exception), do a division by zero
• sigill(): raise a SIGILL signal (Illegal instruction)
• sigsegv(): raise a SIGSEGV signal (Segmentation fault), read memory from NULL (address 0)

sigbus() and sigill() are not available on all operation systems.

The version can be read in the “version” attribute: use “version >> 8” to get the major version, and “version & 255” to get the minor version.

Changelog

Version 1.0 (2010-12-24)

• First public release

Status

• 2010-12-24: Tested with Python 2.6, 3.1 and 3.2 on Debian Sid
• 2010-12-24: Tested with Python 2.6 and 3.1 on Windows XP

Similar projects

Application fault handlers:

• The GNU libc has a fault handler in debug/segfault.c
• XEmacs has a fault handler displaying the Lisp backtrace
• RPy has a fault handler

System-wide fault handlers:

• Ubuntu uses Apport: https://wiki.ubuntu.com/Apport
• The Linux kernel logs also segfaults into /var/log/kern.log (and /var/log/syslog). /proc/sys/kernel/core_pattern contols how coredumps are created.
• Windows opens a popup on a fatal error asking if the error should be reported to Microsoft

See also

• http://bugs.python.org/issue8863 (may 2010): Display Python backtrace on SIGSEGV, SIGFPE and fatal error
• http://bugs.python.org/issue3999 (sept. 2009): Real segmentation fault handler