diff options
| author | Ingo Molnar <mingo@kernel.org> | 2016-09-30 10:54:46 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-09-30 10:54:46 +0200 |
| commit | 0b429e18c284af3e7a39f8ec44d95116c473fef8 (patch) | |
| tree | 7957f57dc70c95a32f71896c9a526ca88b5517ad /kernel/cgroup.c | |
| parent | d32cdbfb0ba319e44f75437afde868f7cafdc467 (diff) | |
| parent | 53061afee43bc5041b67a45b6d793e7afdcf9ca7 (diff) | |
Merge branch 'linus' into locking/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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 de1c1bddb4d1..9ba28310eab6 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) { |