sched_ext: INIT_LIST_HEAD() &sch->all in scx_alloc_and_add_sched()

On scx_link_sched() error paths (parent disabled, hash insert failure),
&sch->all is never added to scx_sched_all. The cleanup path runs
scx_unlink_sched() unconditionally, which calls list_del_rcu(&sch->all) on a
list_head that was never initialized triggering a corruption warning.

Initialize &sch->all.

Fixes: 54be8de ("sched_ext: Factor out scx_link_sched() and scx_unlink_sched()")
Signed-off-by: Tejun Heo <tj@kernel.org>

Author: htejun

kernel/sched/ext.c

@@ -6635,6 +6635,7 @@ static struct scx_sched *scx_alloc_and_add_sched(struct sched_ext_ops *ops,
 	rcu_assign_pointer(ops->priv, sch);
 
 	sch->kobj.kset = scx_kset;
+	INIT_LIST_HEAD(&sch->all);
 
 #ifdef CONFIG_EXT_SUB_SCHED
 	char *buf = kzalloc(PATH_MAX, GFP_KERNEL);