it could get stuck. Fixed by waiting for workers to complete before finishing hotplug cycle. * While CPU hotplug is in progress, idle workers could be depleted which can then lead to deadlock. I think both happening together is highly unlikely but still better to fix it and the fix isn't too scary. There's another workqueue related regression which reported a few days ago: https://bugzilla.kernel.org/show_bug.cgi?id=47301 It's a bit of head scratcher but there is a semi-reliable reproduce case, so I'm hoping to resolve it soonish." * 'for-3.6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq: workqueue: fix possible idle worker depletion across CPU hotplug workqueue: restore POOL_MANAGING_WORKERS workqueue: fix possible deadlock in idle worker rebinding workqueue: move WORKER_REBIND clearing in rebind_workers() to the end of the function workqueue: UNBOUND -> REBIND morphing in rebind_workers() should be atomic ³Î¨r–{x