Thomas Meyer napsal(a):
Rafael J. Wysocki schrieb:
On Sunday, 11 March 2007 21:23, Milan Broz wrote:i tried to boot with nohz=off, but the problem did persist.
Rafael J. Wysocki:Does the problem go away if NO_HZ is unset?
Ah, NO_HZ. Thomas Gleixner's address added to the Cc list.Yes, it's in wait_for_completion() in synchronize_rcu().
short printk traceWell, I think the call to wait_for_completion() does not return, probably
enable_nonboot_cpus
_cpu_up
raw_notifier_callchain (CPU_UP_PREPARE)
...
update_sched_domains
detach_destroy_domains
[waits here] --> synchronize_sched (==synchronize_rcu)
because the task supposed to complete the completion is frozen at this
point. Can you please try to confirm that it gets stuck on
wait_for_completion() in synchronize_rcu()?
As noted in some previous mail, it will wake up after
event - key press etc.
Patch in http://lkml.org/lkml/2007/3/7/255 solves different problem.
I added it to my quilt and applied anyway -> no change.
Hmmmm, both variants (nohz=off or recompiled kernel without NO_HZ) works for me.
Milan