Merge branch 'for-3.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:
 "Two late fixes for cgroup.

  One fixes descendant walk introduced during this rc1 cycle.  The other
  fixes a post 3.9 bug during task attach which can lead to hang.  Both
  fixes are critical and the fixes are relatively straight-forward"

* 'for-3.12-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  cgroup: fix to break the while loop in cgroup_attach_task() correctly
  cgroup: fix cgroup post-order descendant walk of empty subtree
This commit is contained in:
Linus Torvalds 2013-10-22 08:20:34 +01:00
commit ee7eafc907

View File

@ -2039,7 +2039,7 @@ static int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
/* @tsk either already exited or can't exit until the end */
if (tsk->flags & PF_EXITING)
continue;
goto next;
/* as per above, nr_threads may decrease, but not increase. */
BUG_ON(i >= group_size);
@ -2047,7 +2047,7 @@ static int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
ent.cgrp = task_cgroup_from_root(tsk, root);
/* nothing to do if this task is already in the cgroup */
if (ent.cgrp == cgrp)
continue;
goto next;
/*
* saying GFP_ATOMIC has no effect here because we did prealloc
* earlier, but it's good form to communicate our expectations.
@ -2055,7 +2055,7 @@ static int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk,
retval = flex_array_put(group, i, &ent, GFP_ATOMIC);
BUG_ON(retval != 0);
i++;
next:
if (!threadgroup)
break;
} while_each_thread(leader, tsk);
@ -3188,11 +3188,9 @@ css_next_descendant_post(struct cgroup_subsys_state *pos,
WARN_ON_ONCE(!rcu_read_lock_held());
/* if first iteration, visit the leftmost descendant */
if (!pos) {
next = css_leftmost_descendant(root);
return next != root ? next : NULL;
}
/* if first iteration, visit leftmost descendant which may be @root */
if (!pos)
return css_leftmost_descendant(root);
/* if we visited @root, we're done */
if (pos == root)