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RE: [Xen-devel] pvops dom0 20090825 xen_acpi panic

To: Daniel Schroeder <sec@xxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] pvops dom0 20090825 xen_acpi panic
From: "Yu, Ke" <ke.yu@xxxxxxxxx>
Date: Fri, 28 Aug 2009 11:06:22 +0800
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Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
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Thread-topic: [Xen-devel] pvops dom0 20090825 xen_acpi panic
Oh I see. The following patch should fix the panic in bare metal, could you 
please have a try? For the 32bit, I am still trying to reproduce it, will make 
you updated later.

Best Regards


Fix xen_acpi_processor_extcntl_init xen_start_info NULL pointer issue
when kernel runs in bare metal, the xen_start_info could be a NULL pointer,
so add condition check to avoid the kernel panic.

Signed-off-by: Yu Ke <ke.yu@xxxxxxxxx>

diff --git a/drivers/xen/acpi_processor.c b/drivers/xen/acpi_processor.c
index d2b76e9..6a4e8e4 100644
--- a/drivers/xen/acpi_processor.c
+++ b/drivers/xen/acpi_processor.c
@@ -430,10 +430,14 @@ static int xen_hotplug_notifier(struct acpi_processor 
*pr, int event)
 static int __init xen_acpi_processor_extcntl_init(void)
-       unsigned int pmbits = (xen_start_info->flags & SIF_PM_MASK) >> 8;
+       unsigned int pmbits;
-       if (!pmbits)
+       /* Only xen dom0 is allowed to handle ACPI processor info */
+       if (!xen_initial_domain())
                return 0;
+       pmbits = (xen_start_info->flags & SIF_PM_MASK) >> 8;
        if (pmbits & XEN_PROCESSOR_PM_CX)
                xen_ops.pm_ops[PM_TYPE_IDLE] = xen_cx_notifier;
        if (pmbits & XEN_PROCESSOR_PM_PX)

>-----Original Message-----
>From: Daniel Schroeder [mailto:sec@xxxxxxxxxxxxxxx]
>Sent: Friday, August 28, 2009 3:27 AM
>To: Yu, Ke
>Cc: Jeremy Fitzhardinge; xen-devel@xxxxxxxxxxxxxxxxxxx
>Subject: Re: [Xen-devel] pvops dom0 20090825 xen_acpi panic
>Hi Ke,
>> Could you share more info on your configuration, so that I can reproduce it? 
>> E.g.
>is it 32bit dom0 under 64bit hypervisor? Also do you mind attach the
>domi0 .config file?
>this is under a 32bit dom0 but it even happens on bare metal...under kvm
>  the same panic occurs...
>.config is here http://x17.eu/xen_acpi_panic.config.gz

Attachment: pv_ops_null_poiter.patch
Description: pv_ops_null_poiter.patch

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