[PATCH sched_ext/for-6.12-fixes] sched_ext: scx_cgroup_exit() may be called without successful scx_cgroup_init()

From: Tejun Heo
Date: Wed Oct 02 2024 - 16:34:45 EST


568894edbe48 ("sched_ext: Add scx_cgroup_enabled to gate cgroup operations
and fix scx_tg_online()") assumed that scx_cgroup_exit() is only called
after scx_cgroup_init() finished successfully. This isn't true.
scx_cgroup_exit() can be called without scx_cgroup_init() being called at
all or after scx_cgroup_init() failed in the middle.

As init state is tracked per cgroup, scx_cgroup_exit() can be used safely to
clean up in all cases. Remove the incorrect WARN_ON_ONCE().

Signed-off-by: Tejun Heo <tj@xxxxxxxxxx>
Fixes: 568894edbe48 ("sched_ext: Add scx_cgroup_enabled to gate cgroup operations and fix scx_tg_online()")
---
kernel/sched/ext.c | 1 -
1 file changed, 1 deletion(-)

--- a/kernel/sched/ext.c
+++ b/kernel/sched/ext.c
@@ -4119,7 +4119,6 @@ static void scx_cgroup_exit(void)

percpu_rwsem_assert_held(&scx_cgroup_rwsem);

- WARN_ON_ONCE(!scx_cgroup_enabled);
scx_cgroup_enabled = false;

/*