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authorLinus Torvalds <torvalds@linux-foundation.org>2013-10-22 08:20:34 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2013-10-22 08:20:34 +0100
commitee7eafc907db64ef4cbe8a17da3a1089cbe50617 (patch)
tree448cfbb1827083f875729135d4ab0d00b0f0752b
parent0df651a0740c9663093265277c32f0806e8ac23e (diff)
parentea84753c98a7ac6b74e530b64c444a912b3835ca (diff)
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
-rw-r--r--kernel/cgroup.c14
1 files changed, 6 insertions, 8 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2418b6e71a85..8bd9cfdc70d7 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -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)