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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-09-27 16:43:11 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-09-27 16:43:11 -0700 |
| commit | 8ab293e3a1376574e11f9059c09cc0db212546cb (patch) | |
| tree | ab3868ca55ae136df4deb8d70f78faf14b961f90 /kernel/cgroup.c | |
| parent | 08895a8b6b06ed2323cd97a36ee40a116b3db8ed (diff) | |
| parent | 9157056da8f8c4a6305f15619e269f164b63a6de (diff) | |
Merge branch 'for-4.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
"Three late fixes for cgroup: Two cpuset ones, one trivial and the
other pretty obscure, and a cgroup core fix for a bug which impacts
cgroup v2 namespace users"
* 'for-4.8-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup: fix invalid controller enable rejections with cgroup namespace
cpuset: fix non static symbol warning
cpuset: handle race between CPU hotplug and cpuset_hotplug_work
Diffstat (limited to 'kernel/cgroup.c')
| -rw-r--r-- | kernel/cgroup.c | 29 |
1 files changed, 25 insertions, 4 deletions
diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 5e8dab5bf9ad..d6b729beba49 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -3446,9 +3446,28 @@ static ssize_t cgroup_subtree_control_write(struct kernfs_open_file *of, * Except for the root, subtree_control must be zero for a cgroup * with tasks so that child cgroups don't compete against tasks. */ - if (enable && cgroup_parent(cgrp) && !list_empty(&cgrp->cset_links)) { - ret = -EBUSY; - goto out_unlock; + if (enable && cgroup_parent(cgrp)) { + struct cgrp_cset_link *link; + + /* + * Because namespaces pin csets too, @cgrp->cset_links + * might not be empty even when @cgrp is empty. Walk and + * verify each cset. + */ + spin_lock_irq(&css_set_lock); + + ret = 0; + list_for_each_entry(link, &cgrp->cset_links, cset_link) { + if (css_set_populated(link->cset)) { + ret = -EBUSY; + break; + } + } + + spin_unlock_irq(&css_set_lock); + + if (ret) + goto out_unlock; } /* save and update control masks and prepare csses */ @@ -3899,7 +3918,9 @@ void cgroup_file_notify(struct cgroup_file *cfile) * cgroup_task_count - count the number of tasks in a cgroup. * @cgrp: the cgroup in question * - * Return the number of tasks in the cgroup. + * Return the number of tasks in the cgroup. The returned number can be + * higher than the actual number of tasks due to css_set references from + * namespace roots and temporary usages. */ static int cgroup_task_count(const struct cgroup *cgrp) { |