Re: Possible regression with cgroups in 3.11

From: Tejun Heo
Date: Wed Nov 13 2013 - 02:38:27 EST


Hey, guys.

cc'ing people from "workqueue, pci: INFO: possible recursive locking
detected" thread.

http://thread.gmane.org/gmane.linux.kernel/1525779

So, to resolve that issue, we ripped out lockdep annotation from
work_on_cpu() and cgroup is now experiencing deadlock involving
work_on_cpu(). It *could* be that workqueue is actually broken or
memcg is looping but it doesn't seem like a very good idea to not have
lockdep annotation around work_on_cpu().

IIRC, there was one pci code path which called work_on_cpu()
recursively. Would it be possible for that path to use something like
work_on_cpu_nested(XXX, depth) so that we can retain lockdep
annotation on work_on_cpu()?

Thanks.

--
tejun
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