Messages in this thread | | | Date | Tue, 1 Apr 2014 14:18:02 +0100 | From | David Vrabel <> | Subject | Re: [PATCH 3/4] xen/manage: Guard against user-space initiated poweroff and XenBus. |
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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?
David
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