Hello, Li. On Wed, Mar 06, 2013 at 11:28:01AM +0800, Li Zefan wrote: > cgroup_event_wake() is called with hardirq-safe wqh->lock held, so > the nested cgrp->event_list_lock should also be hardirq-safe. > > Fortunately I don't think the deadlock can happen in real life. > > Lockdep never complained, maybe because it never found wqh->lock was > held in irq context? Why should wqh->lock be hard-irq-safe? Is it actually grabbed from irq context? Locks which are grabbed with irq disabled aren't necessarily irq context locks as that doesn't lead to deadlocks. They need to be actually grabbed from irq context. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html