6.1-stable review patch. If anyone has any objections, please let me know.
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From: Chen Ridong chenridong@huawei.com
commit 37fb58a7273726e59f9429c89ade5116083a213d upstream.
An issue was found:
# cd /sys/fs/cgroup/freezer/ # mkdir test # echo FROZEN > test/freezer.state # cat test/freezer.state FROZEN # sleep 1000 & [1] 863 # echo 863 > test/cgroup.procs # cat test/freezer.state FREEZING
When tasks are migrated to a frozen cgroup, the freezer fails to immediately freeze the tasks, causing the cgroup to remain in the "FREEZING".
The freeze_task() function is called before clearing the CGROUP_FROZEN flag. This causes the freezing() check to incorrectly return false, preventing __freeze_task() from being invoked for the migrated task.
To fix this issue, clear the CGROUP_FROZEN state before calling freeze_task().
Fixes: f5d39b020809 ("freezer,sched: Rewrite core freezer logic") Cc: stable@vger.kernel.org # v6.1+ Reported-by: Zhong Jiawei zhongjiawei1@huawei.com Signed-off-by: Chen Ridong chenridong@huawei.com Acked-by: Michal Koutný mkoutny@suse.com Signed-off-by: Tejun Heo tj@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/cgroup/legacy_freezer.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/kernel/cgroup/legacy_freezer.c +++ b/kernel/cgroup/legacy_freezer.c @@ -189,13 +189,12 @@ static void freezer_attach(struct cgroup if (!(freezer->state & CGROUP_FREEZING)) { __thaw_task(task); } else { - freeze_task(task); - /* clear FROZEN and propagate upwards */ while (freezer && (freezer->state & CGROUP_FROZEN)) { freezer->state &= ~CGROUP_FROZEN; freezer = parent_freezer(freezer); } + freeze_task(task); } }