WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Xen

xen-devel

[Top] [All Lists]

Re: [Xen-devel] Xen PANIC in MCE interrupt context : can global variable

To: "Yunhong Jiang" <yunhong.jiang@xxxxxxxxx>, "Ashwin Pankaj" <ashwin.pankaj@xxxxxxx>
Subject: Re: [Xen-devel] Xen PANIC in MCE interrupt context : can global variable dom0 be NULL ?
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: 2010年2月16日 09:05:33 +0000
Cc: Xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: 2010年2月16日 01:06:17 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4B795809.5070304@xxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <4B795809.5070304@xxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
>>> Ashwin Pankaj <ashwin.pankaj@xxxxxxx> 15.02.10 15:19 >>>
> After some digging, probable culprit seems to be smp_cmci_interrupt
>
>> if (bs.errcnt && mctc != NULL) {
>> if (guest_enabled_event(dom0->vcpu[0], 
>> <------------------------------------ here
>> VIRQ_MCA)) {
>> mctelem_commit(mctc);
>> printk(KERN_DEBUG "CMCI: send CMCI to DOM0 through virq\n");
>> send_guest_global_virq(dom0, VIRQ_MCA);
>> } else {
>> x86_mcinfo_dump(mctelem_dataptr(mctc));
>> mctelem_dismiss(mctc);
>> }
>
>
>Looks like dom0 is NULL here ( vcpu[0] offset is 0x468). Is this possible?
Yes, your call trace confirms this.
>Other functions like mce_softirq() perform a NULL check on dom0 before 
>accessing it's members ....
The majority of uses doesn't seem to do that check, yet it is essential
if CMCIs occur during boot of Xen. Even more, it should not only be
dom0 that is checked against NULL, but also dom0->vcpu (or
dom0->max_vcpus) and dom0->vcpu[0].
Jan
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel
<Prev in Thread] Current Thread [Next in Thread>
Previous by Date: [Xen-devel] RE: Tmem vs order>0 allocation, workaround RFC , Jan Beulich
Next by Date: RE: [Xen-devel] Xen PANIC in MCE interrupt context : can global variable dom0 be NULL ? , Jiang, Yunhong
Previous by Thread: [Xen-devel] Xen PANIC in MCE interrupt context : can global variable dom0 be NULL ? , Ashwin Pankaj
Next by Thread: RE: [Xen-devel] Xen PANIC in MCE interrupt context : can global variable dom0 be NULL ? , Jiang, Yunhong
Indexes: [Date] [Thread] [Top] [All Lists]

Copyright ©, Citrix Systems Inc. All rights reserved. Legal and Privacy
Citrix This site is hosted by Citrix

AltStyle によって変換されたページ (->オリジナル) /