[New-bugs-announce] [issue24283] Print not safe in signal handlers

Devin Jeanpierre report at bugs.python.org
Mon May 25 10:37:41 CEST 2015

New submission from Devin Jeanpierre:

The code attached runs a while loop that prints, and has a signal handler that also prints. There is a thread that constantly fires off signals, but this is just to ensure the condition for the bug happens -- this is a bug with signal handling, not threads -- I can trigger a RuntimeError (... with a missing message?) by commenting out the threading lines and instead running a separate process "while true; do kill -s SIGUSR1 4687; done".


$ python3 threading_print_test.py 
Traceback (most recent call last):
  File "/usr/local/google/home/devinj/Downloads/threading_print_test.py", line 36, in <module>
  File "/usr/local/google/home/devinj/Downloads/threading_print_test.py", line 30, in main
  File "/usr/local/google/home/devinj/Downloads/threading_print_test.py", line 13, in print_hello
RuntimeError: reentrant call inside <_io.BufferedWriter name='<stdout>'>

files: threading_print_test.py
messages: 244020
nosy: Devin Jeanpierre, haypo
priority: normal
severity: normal
status: open
title: Print not safe in signal handlers
Added file: http://bugs.python.org/file39491/threading_print_test.py

Python tracker <report at bugs.python.org>

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