>> From: "Dave Korn" <[EMAIL PROTECTED]>
>> To: <cygwin@cygwin.com>
>> Date: Fri, 22 Jul 2005 11:47:40 +0100
>> Subject: RE: Known issues with Pthreads in 1.5.18?
>> The default type of mutex just got changed, from error checking, to
>> normal. If your code is setting up a default mutex and then one thread
>> attempts to recursively take the mutex, it will now deadlock where before it
>> would have succeeded. Or it may be possible your code is unlocking the
>> mutex more times than it takes it, which would probably show the same
>> symptom. See the thread starting at:
>>
>> http://www.cygwin.com/ml/cygwin/2005-05/msg01298.html
>>
>> and the announcment for 1.5.18
>>
>> http://www.cygwin.com/ml/cygwin-announce/2005-07/msg00001.html
>>
>> in particular the line that says
>>
>> "cgf: Change default value for PTHREAD_MUTEX_DEFAULT to PTHREAD_NORMAL."
>>
>>
>> cheers,
>> DaveK
Unfortunately that seems to have borked Python 2.4. I found that out the hard
way after returning from a week offline, I just upgraded everything to 1.5.18
and as a result dequeuing operations stopped blocking and started getting
"temp. unavailable" errors. No, I didn't bother saving the messages nor the
configuration. Going back to older versions was a huge pain (at least when
using setup.exe because an accidental/exploratory click could cause a newer
version of a package to be selected which would prereq 1.5.18 again..
anyways)...
Since I don't have a second machine to infect with 1.5.18, I cannot directly
re-produce this. My code used Python threads, one consumer, one producer.
Instead of the consumer blocking, it would get an error trying to get a mutex,
"resource temporarily unavailable." I have no idea if this is a bug in the
python Queue code, python threading, or just an unexpected side-effect of
changing mutex behaviour. Scanning the archives it didn't seem obvious that
anyone else had seen this...
Since I'm not in a position to "fix this myself", I can offer to exchange toy
python programs with someone who can, in an effort to track down where the bug
is originating.
Thanks,
--Doug
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