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| author | Waiman Long <longman@redhat.com> | 2024-08-09 05:22:59 +0200 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2024-08-09 18:35:29 +0200 |
| commit | 9b103943ab281d137df1cdb48dcef329a87e0a06 (patch) | |
| tree | 3033951ffe36063dedf14a411a8c2544dcfadacb /kernel | |
| parent | selftest/cgroup: Add new test cases to test_cpuset_prs.sh (diff) | |
| download | linux-9b103943ab281d137df1cdb48dcef329a87e0a06.tar.xz linux-9b103943ab281d137df1cdb48dcef329a87e0a06.zip | |
cgroup: Fix incorrect WARN_ON_ONCE() in css_release_work_fn()
It turns out that the WARN_ON_ONCE() call in css_release_work_fn
introduced by commit ab0312526867 ("cgroup: Show # of subsystem CSSes
in cgroup.stat") is incorrect. Although css->nr_descendants must be
0 when a css is released and ready to be freed, the corresponding
cgrp->nr_dying_subsys[ss->id] may not be 0 if a subsystem is activated
and deactivated multiple times with one or more of its previous
activation leaving behind dying csses.
Fix the incorrect warning by removing the cgrp->nr_dying_subsys check.
Fixes: ab0312526867 ("cgroup: Show # of subsystem CSSes in cgroup.stat")
Closes: https://lore.kernel.org/cgroups/6f301773-2fce-4602-a391-8af7ef00b2fb@redhat.com/T/#t
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/cgroup/cgroup.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/kernel/cgroup/cgroup.c b/kernel/cgroup/cgroup.c index 601600afdd20..244ec600b4d8 100644 --- a/kernel/cgroup/cgroup.c +++ b/kernel/cgroup/cgroup.c @@ -5465,7 +5465,14 @@ static void css_release_work_fn(struct work_struct *work) ss->css_released(css); cgrp->nr_dying_subsys[ss->id]--; - WARN_ON_ONCE(css->nr_descendants || cgrp->nr_dying_subsys[ss->id]); + /* + * When a css is released and ready to be freed, its + * nr_descendants must be zero. However, the corresponding + * cgrp->nr_dying_subsys[ss->id] may not be 0 if a subsystem + * is activated and deactivated multiple times with one or + * more of its previous activation leaving behind dying csses. + */ + WARN_ON_ONCE(css->nr_descendants); parent_cgrp = cgroup_parent(cgrp); while (parent_cgrp) { parent_cgrp->nr_dying_subsys[ss->id]--; |