On 26/11/13 16:45, Konrad Rzeszutek Wilk wrote: > On Thu, Nov 21, 2013 at 11:09:52AM +0000, David Vrabel wrote: >> On 08/11/13 17:38, Konrad Rzeszutek Wilk wrote: >>> There is a race case where the user does 'poweroff' >>> and at the same time the system admin does 'xl shutdown'. >> >> This isn't a Xen-specific problem is it? Wouldn't it be better to fix >> this in generic code? > > Possibly. I believe the reason for the reboot_notifier to exist is > to provide a means to fix the race. > >> >> Especially since I don't think this patch actually fixes the race >> completely. >> >>> --- a/drivers/xen/manage.c >>> +++ b/drivers/xen/manage.c >> [...] >>> @@ -222,7 +230,7 @@ static void shutdown_handler(struct xenbus_watch *watch, >>> }; >>> static struct shutdown_handler *handler; >>> >>> - if (shutting_down != SHUTDOWN_INVALID) >>> + if (atomic_read(&shutting_down) != SHUTDOWN_INVALID) >>> return; >> >> In guest initiated poweroff at this time will still race with this >> toolstack initiated poweroff. > > No, b/c the reboot notifier would have set 'shutting_down' already.
If the guest initiated power off is started here, the reboot notifier won't have run yet. David -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
