ee3f73a133
The fasteners lib in version 0.15.0 removed the
threading.current_thread workaround for eventlet[1] because eventlet
seemed to fixed the current_thread issues tracked in [2]. However the
fix for [2] only fixed half of the problem. The threading.current_thread
call works if it is called from thread created by eventlet.spawn.
However if the thread is created with eventlet.spawn_n then
threading.current_thread is still broken and returns the ID of the
python native thread.
The fasteners' ReaderWriterLock depends heavily on
threading.current_thread to decide which thread holds a lock and to
allow re-entry of that thread. This leads to the situation that
multiple threads created from spawn_n could take the same
ReaderWriterLock at the same time.
The fair internal lock in oslo.concurrency uses ReaderWriterLock and
as a result such lock is broken for threads created with spawn_n.
Note that this issue was raised with eventlet in [3] when the nova team
detected it via a direct usage of ReaderWriterLock in the nova test
code. As [3] did not lead to a solution in eventlet nova implemented a
nova local fix for the test code in [4].
However now we detected that oslo.concurrency is affected by this issue
as well.
This patch restores the workaround that was removed by [1].
Note that a fasteners issue [5] also opened to restore the
workaround[1].
[1] 467ed75ee1
[2] https://github.com/eventlet/eventlet/issues/172
[3] https://github.com/eventlet/eventlet/issues/731
[4] https://review.opendev.org/c/openstack/nova/+/813114
[5] https://github.com/harlowja/fasteners/issues/96
Closes-Bug: #1988311
Change-Id: Ia873bcc6b07121c9bd0b94c593567d537b4c1112
Team and repository tags
oslo.concurrency
The oslo.concurrency library has utilities for safely running multi-thread, multi-process applications using locking mechanisms and for running external processes.
- Free software: Apache license
- Documentation: https://docs.openstack.org/oslo.concurrency/latest/
- Source: https://opendev.org/openstack/oslo.concurrency
- Bugs: https://bugs.launchpad.net/oslo.concurrency
- Release Notes: https://docs.openstack.org/releasenotes/oslo.concurrency/