From: David Vrabel <david.vrabel@citrix.com>
To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: <Ian.Campbell@citrix.com>, <xen-devel@lists.xenproject.org>,
<linux-kernel@vger.kernel.org>, <JBeulich@suse.com>,
<boris.ostrovsky@oracle.com>
Subject: Re: [PATCH 3/4] xen/manage: Guard against user-space initiated poweroff and XenBus.
Date: Tue, 1 Apr 2014 14:18:02 +0100 [thread overview]
Message-ID: <533ABC8A.5080405@citrix.com> (raw)
In-Reply-To: <1383932286-25080-4-git-send-email-konrad.wilk@oracle.com>
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
next prev parent reply other threads:[~2014-04-01 13:18 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-08 17:38 [PATCH] Fixes to Linux v3.13 - bugs.xenproject.org ones. (v1) Konrad Rzeszutek Wilk
2013-11-08 17:38 ` [PATCH 1/4] xen/mcfg: Call PHYSDEVOP_pci_mmcfg_reserved for MCFG areas Konrad Rzeszutek Wilk
2013-11-21 10:37 ` David Vrabel
2013-11-08 17:38 ` [PATCH 2/4] xen/manage: Poweroff forcefully if user-space is not yet up Konrad Rzeszutek Wilk
2013-11-20 21:11 ` Boris Ostrovsky
2013-11-21 11:33 ` David Vrabel
2013-11-26 16:47 ` Konrad Rzeszutek Wilk
2014-04-01 15:43 ` Konrad Rzeszutek Wilk
2013-11-08 17:38 ` [PATCH 3/4] xen/manage: Guard against user-space initiated poweroff and XenBus Konrad Rzeszutek Wilk
2013-11-20 21:40 ` Boris Ostrovsky
2013-11-21 11:09 ` David Vrabel
2013-11-26 16:45 ` Konrad Rzeszutek Wilk
2013-12-02 11:27 ` David Vrabel
2014-03-31 19:09 ` Konrad Rzeszutek Wilk
2014-04-01 13:18 ` David Vrabel [this message]
2014-04-01 14:03 ` Konrad Rzeszutek Wilk
2013-11-08 17:38 ` [PATCH 4/4] xen/xenbus: Avoid synchronous wait on XenBus stalling shutdown/restart Konrad Rzeszutek Wilk
2013-11-21 17:52 ` [Xen-devel] " David Vrabel
2013-11-22 9:30 ` Ian Campbell
2013-11-26 16:50 ` Konrad Rzeszutek Wilk
2013-12-02 11:41 ` David Vrabel
2014-03-31 20:33 ` Konrad Rzeszutek Wilk
2014-04-01 12:53 ` David Vrabel
2014-01-26 1:13 ` Zhang, Yang Z
2014-01-26 3:44 ` Konrad Rzeszutek Wilk
2014-04-03 11:59 ` [PATCH] Fixes to Linux v3.13 - bugs.xenproject.org ones. (v1) David Vrabel
2014-04-03 18:07 ` Konrad Rzeszutek Wilk
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