Warn when a RPC call is made while a lock is held

[Michael Still]

We shouldn't be making RPC calls while a lock is held, as it blocks other users of the lock waiting on the RPC to return. This came up for me with the iptables lock and a call to nova-network which is being tracked in bug 1062314. I would like to see a generic warning being issued when this scenario occurs, so that we know to track down these things when they happen.

[Davanum Srinivas (DIMS) (dims-v)]

Any ideas on how this can be implemented?

[Davanum Srinivas (DIMS) (dims-v)]

Looks like this is in progress with a patch against oslo - https://review.openstack.org/#/c/14804/

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/21406

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/21406
Committed: http://github.com/openstack/nova/commit/1cfc526f50686286e64ac07566f715e981916d3c
Submitter: Jenkins
Branch: master

commit 1cfc526f50686286e64ac07566f715e981916d3c
Author: Michael Still <email address hidden>
Date: Thu Feb 7 16:04:17 2013 +1100

    Update modules from common required for rpc with lock detection.

    This change updates the versions of the local, lockutils and rpc
    modules from common. This is required so that I can implement
    automated detection of rpcs being made while holding locks, which
    will come in a later review.

    Sneaks up on bug 1063222.

    Change-Id: I3689c133d1efc7425a44662abbdb434b5f36c64e

[Tracy Jones (tjones-i)]

Michael - is this still an issue? A patch was merged for it...

[Joe Gordon (jogo)]

unclear why this bug was re-opened. Michael can you elaborate.

[Sean Dague (sdague)]

I'm moving back to fixed because no one knows why the bug was reopened.