Re: ~90s reboot delay with v6.19 and PREEMPT_RT

[Sebastian Andrzej Siewior]

On 2026-02-25 23:31:36 [+0100], To Bert Karwatzki wrote:
…
> Until the sched_switch, everything is the same. But then systemd-1828
> (the one with the cgroup_notify_populated event) seems to get impatient
> and sends a SIGTERM+SIGCONT. It gets the exit code, the
> cgroup_notify_populated event is there later and just once. The
> app.slice notify is missing. And the rmdir gets in much later.
…

I so proud of myself. Bert, can you confirm that this works?

--- a/kernel/cgroup/cgroup.c
+++ b/kernel/cgroup/cgroup.c
@@ -5283,6 +5283,11 @@ static void *cgroup_procs_start(struct seq_file *s, loff_t *pos)
 
 static int cgroup_procs_show(struct seq_file *s, void *v)
 {
+	struct task_struct *tsk = v;
+
+	if (READ_ONCE(tsk->__state) & TASK_DEAD)
+		return 0;
+
 	seq_printf(s, "%d\n", task_pid_vnr(v));
 	return 0;
 }
-- 
2.51.0

Sebastian