On Tue, Aug 10, 2010 at 09:53:21PM +0200, Tomasz Buchert wrote: > Writing 'FROZEN' to freezer.state file does not > forbid the task to be moved away from its cgroup > (for a very short time). Nevertheless the moved task > can become frozen OUTSIDE its cgroup which puts > discussed task in a permanent 'D' state. > > This patch forbids migration of either FROZEN > or FREEZING tasks. > > This behavior was observed and easily reproduced on > a single core laptop. Program and instructions how > to reproduce the bug can be fetched from: > http://pentium.hopto.org/~thinred/repos/linux-misc/freezer_bug.c Thanks for the report and the test code. I'm will try to reproduce this race in the next few hours and analyze it since I'm not sure the patch really fixes the race -- it may only make the race trigger less frequently. At the very least the patch won't break the current code since it's essentially a more-strict version of is_task_frozen_enough() -- it lets fewer tasks attach/detach to/from frozen cgroups. Cheers, -Matt Helsley _______________________________________________ Containers mailing list Containers@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/containers
