[Python-Dev] Issue #8863 adds a new PYTHONNOFAULTHANDLER?environment variable (original) (raw)

Victor Stinner vstinner at edenwall.com
Mon Dec 20 16:33:12 CET 2010

Le lundi 20 décembre 2010 15:55:57, Stefan Krah a écrit :

> The backtrace is valid. Don't you think that this backtrace is more > useful than just "Segmentation fault"?

Perhaps I misunderstood, but I thought the purpose of the patch was to let developers act more quickly on bug reports. I wonder if this output really speeds up the process.

The fault handler helps developers because they don't have to have a Python compiled in debug mode and to run the application in a debugger (like gdb).

If the developer is unable to reproduce an error, because it's an Heisenbug, or because the developer doesn't have the same OS, libraries and/or applications, the fault handler helps the developer to isolate the problem.

Many bugs only occur once and you cannot report a bug report because you don't have any useful information.

But the fault handler doesn't help graphical applications not started from a terminal...

Do you have an example bug where this patch helps in finding the precise location of a segfault?

Any bug report which only contain "Segmentation fault" information. But I cannot give you a revelant example because users are too shy to report an issue if they don't have more information than just "the program crashed". With a fault handler displaying the Python backtrace, I hope that more users will report bugs.

Example of an issue with only the "Segmentation fault" information: http://bugs.python.org/issue6011#msg121551 I am unable to reproduce this crash, and I'm very frustrated because I want to fix it! :-)

Another example which might benefit from the fault handler: http://bugs.python.org/issue7424

Compiling /usr/pkg/lib/python2.6/test/test_builtin.py ... [1] Segmentation fault (core dumped) PYTHONPATH=/usr/... *** Error code 139

If the reporter already wrote a minimal script, it doesn't help. The fault handler helps to write the minimal script (to isolate the bug).

I did use version 10. I've verified the same behavior with a fresh py3k checkout and this patch: (...)

My machine currently has a load average of 2. Perhaps you'll be able to reproduce it if you crank up the load average.

What is your OS (name, version)? I only tested crashers on Linux (Debian Sid).

Victor

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