[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH 3/4] xen/manage: Guard against user-space initiated poweroff and XenBus.
On Tue, Apr 01, 2014 at 02:18:02PM +0100, 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'. > > > > Depending on the race, the system_state will be SYSTEM_RUNNING or > > SYSTEM_POWER_OFF. If SYSTEM_RUNNING we just end up making > > a duplicate call to 'poweroff' (while it is running). > > > > That will fail or execute (And if executed then it will be > > stuck in the reboot_mutex mutex). But nobody will care b/c the > > machine is in poweroff sequence. > > If this race isn't a problem... > > > If the system_state is SYSTEM_POWER_OFF then we end up making > > a duplicate call to kernel_power_off. There is no locking > > there so we walk in the same steps as what 'poweroff' > > has been doing. > > ... and this one doesn't happen because do_power_off() calls > orderly_poweroff(false) so does not call kernel_power_off(). > > Then isn't the patch unnecessary? Yup :-) I realized that once I wrote up the race condition. > > David _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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