On Fri, Apr 27, 2012 at 7:39 PM, Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote: > On Fri, Apr 27, 2012 at 03:02:22PM +0900, KAMEZAWA Hiroyuki wrote: >> attach_task() is done under cgroup_mutex() but ->pre_destroy() callback >> in rmdir() isn't called under cgroup_mutex(). >> >> It's better to avoid attaching a task to a cgroup which >> is under pre_destroy(). Considering memcg, the attached task may >> increase resource usage after memcg's pre_destroy() confirms that >> memcg is empty. This is not good. >> >> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> >> --- >> kernel/cgroup.c | 5 ++++- >> 1 files changed, 4 insertions(+), 1 deletions(-) >> >> diff --git a/kernel/cgroup.c b/kernel/cgroup.c >> index ad8eae5..7a3076b 100644 >> --- a/kernel/cgroup.c >> +++ b/kernel/cgroup.c >> @@ -1953,6 +1953,9 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) >> if (cgrp == oldcgrp) >> return 0; >> >> + if (test_bit(CGRP_WAIT_ON_RMDIR, &cgrp->flags)) >> + return -EBUSY; >> + > > You probably need to update cgroup_attach_proc() as well? > Ahh...I missed that. Thank you for pointing out ! Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href