blocked on futex

Aahz aahz at
Sun Mar 29 16:12:51 CEST 2009

In article <7aea1500-aebc-4585-97c3-ba15f5dc79ab at>,
msoulier  <msoulier at> wrote:
>On Mar 25, 10:27=A0am, a... at (Aahz) wrote:
>> That's a bit bizarre. =A0You're correct that if this is a Python bug, the=
>> will be no fixes available. =A0However, you said earlier that this is a
>> patched Python, so I'm wondering whether the applied patch is broken.
>> Assuming I'm reading this correctly, it's hanging when trying to emit a
>> top-level exception using PyErr_Display.
>Actually, I think that I may have found the problem.
>I have calls to a standard python logger object in a signal handler,
>and I think the logging api is synchronized, so that it calls
>pthread_mutex_lock() when on Linux. This is a no-no from a signal
>handler. I've removed the offending calls and so far I am unable to
>get the process to lock-up again, so I think I may have found it.
>As such, I'd say it's my bug and not Python's.

Great!  That would also explain the traceback since I think signal
handlers get called from the top level.
Aahz (aahz at           <*>

"At Resolver we've found it useful to short-circuit any doubt and just
refer to comments in code as 'lies'. :-)"
--Michael Foord paraphrases Christian Muirhead on python-dev, 2009-3-22

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