[New-bugs-announce] [issue29335] Python 2.7 subprocess module does not check WIFSTOPPED on SIGCHLD

[Zach Riggle]

New submission from Zach Riggle:

The attached script hits some "This should never happen" code in the subprocess module.

These lines here:
https://github.com/python/cpython/blob/2.7/Lib/subprocess.py#L1036-L1038

The root cause is a lack of checking WIFSTOPPED and WSTOPSIG in the handler.

When a process elects into being ptraced via PTRACE_TRACEME, it is stopped on the SIGSEGV instead of terminating, allowing the user to attach a debugger before the kernel destroys the process.

This bug makes it impossible to wait on any process which crashes, which is set up to wait for a debugger.

----------
components: Library (Lib)
files: bug.py
messages: 285921
nosy: Zach Riggle
priority: normal
severity: normal
status: open
title: Python 2.7 subprocess module does not check WIFSTOPPED on SIGCHLD
versions: Python 2.7
Added file: http://bugs.python.org/file46363/bug.py

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue29335>
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