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[bugs #8374] Latest Modifications:
Changes by:
Willem Rein Oudshoorn <[EMAIL PROTECTED]>
'Date:
Thu 04/01/04 at 13:29 (Europe/Amsterdam)
------------------ Additional Follow-up Comments ----------------------------
Seems to have solved my problems.
About the new bugs, I don't know :-)
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[bugs #8374] Full Item Snapshot:
URL: <http://savannah.gnu.org/bugs/?func=detailitem&item_id=8374>
Project: GNUstep
Submitted by: Willem Rein Oudshoorn
On: Tue 03/30/04 at 13:13
Category: Base/Foundation
Severity: 3 - Ordinary
Item Group: Bug
Resolution: Fixed
Assigned to: None
Status: Closed
Summary: NSNotificationCenter can deadlock
Original Submission: There is a lock protecting the list of notifications.
This lock is grabbed before sending the notifications and released after sending the
notifications.
This can lead to a deadlock when multiple threads are using the notification center.
The attached program shows in a very artificial situation how the deadlock can occur.
I just spend 3 days figuring this out in a complicated situation involving multiple
threads, DO and launched tasks.
So it is not just a theoretical problem.
I have not looked deeply at it, but probably just
making a copy instead of maintaining the lock will solve it.
(But I have to look again.)
Wim Oudshoorn
Follow-up Comments
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Date: Thu 04/01/04 at 13:29 By: wim
Seems to have solved my problems.
About the new bugs, I don't know :-)
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Date: Wed 03/31/04 at 13:26 By: CaS
We use DO and notifications in a threaded environment (inside java servlet engine)
where I work, so a possible deadlock there is potentially a serious issue for us ...
so I spent a
bit of company time on this.
I've rewritten the notification posting code to post when the center is unlocked (and
also simplified it a bit). This seems to fix your problem and I haven't had any other
trouble with it.
Please can you try it out (the changes are in CVS now) and let me know if I've
introduced any other bugs :-)
File Attachments
-------------------
-------------------------------------------------------
Date: Tue 03/30/04 at 13:13 Name: deadlocktest.tar.gz Size: 837KB By: wim
Example of NSNotificationCenter deadlock.
http://savannah.gnu.org/bugs/download.php?item_id=8374&item_file_id=1143
For detailed info, follow this link:
<http://savannah.gnu.org/bugs/?func=detailitem&item_id=8374>
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