Hello, cgroup currently only blocks new threads from joining the target threadgroup during migration, and on-going migration could race against exec and exit leading to interesting problems - the symmetry between various attach methods, task exiting during method execution, ->exit() racing against attach methods, migrating task switching basic properties during exec and so on. This patchset extends threadgroup locking such that it covers all operations which can alter the threadgroup - fork, exit and exec, and update cgroup to take advantage of it. rwsem read ops are added to exit path but exec is excluded by grabbing the existing cred_guard_mutex from threadgroup locking helper. This makes threadgroup locking complete and resolves cgroup issues stemming from the target taskset being unstable. This patchset is on top of the current pm-freezer + "freezer: fixes & simplifications" patchset and contains the following four patches. Patch list and diffstat follow. Thanks. [PATCH 1/4] cgroup: change locking order in attach_task_by_pid() [PATCH 2/4] threadgroup: rename signal->threadgroup_fork_lock to [PATCH 3/4] threadgroup: extend threadgroup_lock() to cover exit and [PATCH 4/4] cgroup: always lock threadgroup during migration include/linux/init_task.h | 9 ++---- include/linux/sched.h | 58 ++++++++++++++++++++++++++++--------------- kernel/cgroup.c | 62 +++++++++++++++++++++------------------------- kernel/exit.c | 16 ++++++++--- kernel/fork.c | 8 ++--- 5 files changed, 88 insertions(+), 65 deletions(-) -- tejun [1] http://thread.gmane.org/gmane.linux.kernel/1187553 _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
