From: Chen Ridong <[email protected]>
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: [email protected] # v6.1+
Reported-by: Zhong Jiawei <[email protected]>
Signed-off-by: Chen Ridong <[email protected]>
Acked-by: Michal Koutný <[email protected]>
Signed-off-by: Tejun Heo <[email protected]>
https://virtuozzo.atlassian.net/browse/VSTOR-118578
(cherry picked from commit 37fb58a7273726e59f9429c89ade5116083a213d)
Signed-off-by: Pavel Tikhomirov <[email protected]>
Feature: cgroup/freeze: improvements
---
kernel/cgroup/legacy_freezer.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/kernel/cgroup/legacy_freezer.c b/kernel/cgroup/legacy_freezer.c
index 23035df43a0e0..10b643dd570db 100644
--- a/kernel/cgroup/legacy_freezer.c
+++ b/kernel/cgroup/legacy_freezer.c
@@ -193,13 +193,12 @@ static void freezer_attach(struct cgroup_taskset *tset)
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);
}
}
--
2.51.1
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