On 07/05/2017 10:05 AM, Juergen Gross wrote:
> Commit dc6416f1d711eb4c1726e845d653235dcaae12e1 ("xen/x86: Call
> cpu_startup_entry(CPUHP_AP_ONLINE_IDLE) from xen_play_dead()")
> introduced an error leading to a stack overflow of the idle task when
> a cpu was brought offline/online many times: by calling
> cpu_startup_entry() instead of returning at the end of xen_play_dead()
> do_idle() would be entered again and again.
>
> Don't use cpu_startup_entry(), but cpuhp_online_idle() instead allowing
> to return from xen_play_dead().
>
> Cc: <stable@xxxxxxxxxxxxxxx> # 4.12
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx>