Re: [Bug #11989] Suspend failure on NForce4-based boards due to chanes in stop_machine

Vegard Nossum
2008-11-11T14:47:56Z

On Tue, Nov 11, 2008 at 11:52 AM, Ingo Molnar <mingo-X9Un+BFzKDI@public.gmane.org> wrote:
> [ Cc:-ed workqueue/locking/suspend-race-condition experts. ]
>
> Seems like the new kernel/stop_machine.c logic has a race for the test
> sequence above. (Below is the bisected commit again, maybe the race is
> visible via email review as well.)

I try again.

I think that the test for stop_machine_data in stop_cpu() should not
have been moved from __stop_machine(). Because now cpu_online_map may
change in-between calls to stop_cpu() (if the callback tries to
online/offline CPUs), and the end result may be different.

Maybe?

Vegard