Deadlock on poweroff

Kirill A. Shutemov
2012-10-07T02:46:32Z

Hi Paul and all,

With commit 755609a9087fa983f567dc5452b2fa7b089b591f I've got deadlock on
poweroff.

It guess it happens because of race for cpu_hotplug.lock:

CPU A CPU B
disable_nonboot_cpus()
_cpu_down()
cpu_hotplug_begin()
mutex_lock(&cpu_hotplug.lock);
__cpu_notify()
padata_cpu_callback()
__padata_remove_cpu()
padata_replace()
synchronize_rcu()
rcu_gp_kthread()
get_online_cpus();
mutex_lock(&cpu_hotplug.lock);

Have you seen the issue before?

--
Kirill A. Shutemov