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    SubjectRe: [PATCH 3/4] xen/manage: Guard against user-space initiated poweroff and XenBus.
    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?

    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.

    David


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