Merge tag 'cgroup-for-6.16-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup

Pull cgroup fixes from Tejun Heo:
 "An earlier commit to suppress a warning introduced a race condition
  where tasks can escape cgroup1 freezer. Revert the commit and simply
  remove the warning which was spurious to begin with"

* tag 'cgroup-for-6.16-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
  Revert "cgroup_freezer: cgroup_freezing: Check if not frozen"
  sched,freezer: Remove unnecessary warning in __thaw_task

Author: torvalds

kernel/cgroup/legacy_freezer.c

@@ -66,15 +66,9 @@ static struct freezer *parent_freezer(struct freezer *freezer)
 bool cgroup_freezing(struct task_struct *task)
 {
 	bool ret;
-	unsigned int state;
 
 	rcu_read_lock();
-	/* Check if the cgroup is still FREEZING, but not FROZEN. The extra
-	 * !FROZEN check is required, because the FREEZING bit is not cleared
-	 * when the state FROZEN is reached.
-	 */
-	state = task_freezer(task)->state;
-	ret = (state & CGROUP_FREEZING) && !(state & CGROUP_FROZEN);
+	ret = task_freezer(task)->state & CGROUP_FREEZING;
 	rcu_read_unlock();
 
 	return ret;

kernel/freezer.c

@@ -201,18 +201,9 @@ static int __restore_freezer_state(struct task_struct *p, void *arg)
 
 void __thaw_task(struct task_struct *p)
 {
-	unsigned long flags;
-
-	spin_lock_irqsave(&freezer_lock, flags);
-	if (WARN_ON_ONCE(freezing(p)))
-		goto unlock;
-
-	if (!frozen(p) || task_call_func(p, __restore_freezer_state, NULL))
-		goto unlock;
-
-	wake_up_state(p, TASK_FROZEN);
-unlock:
-	spin_unlock_irqrestore(&freezer_lock, flags);
+	guard(spinlock_irqsave)(&freezer_lock);
+	if (frozen(p) && !task_call_func(p, __restore_freezer_state, NULL))
+		wake_up_state(p, TASK_FROZEN);
 }
 
 /**