[Xen-devel] [PATCH] Fix qemu-dm segfault when multiple HVM domains ---Was: qemu-dm segfault with multiple HVM domains?

["Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>]

 Hi,  John
        Can you try the attached patch ? 

        This issue can be reproduced on SMP platform, while the domain 0
is UP. The reason is, after finishing a dma request, the dma thread will
trigger the interrupt and then clear the call back function. When guest
get the interrupt , it will try to check the call back function, if it
is set, then it will trigger a dma request again. So if the checking for
the callbackfunction happens between trigger interrupt and clear
callback function on dma thread, it will cause NULL function calling.
After with domain 0 UP and smp platform, this situation can be
reproduced easily.

Thanks
Yunhong Jiang


This patch fix this issue by placing the interupt request in the end of
dma thread.
>-----Original Message-----
>From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx 
>[mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of 
>John Clemens
>Sent: Thursday, February 23, 2006 6:12 AM
>To: Li, Xin B
>Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
>Subject: RE: [Xen-devel] qemu-dm segfault with multiple HVM domains?
>
>
>Thanks, glad to know I'm not the only one seeing this...  I've opened 
>bug 542.
>
>http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=542
>
>john.c
>
>- --
>John Clemens                   jclemens@xxxxxxxxxxxxxxx
>
>On Thu, 23 Feb 2006, Li, Xin B wrote:
>
>>> Just verifying that with cs 8932 I still see this problem.
>>> I'm able to
>>> start multiple windows domains, but either immediately or over
>>> time all
>>> but one qemu-dm processes segfaults.  This only appears to be
>>> a problem
>>> when I start multiple windows domains, a single domain seems
>>> to work fine.
>>>
>>> qemu-dm[4961]: segfault at 0000000000000000 rip 0000000000000000 rsp
>>> 0000000040800198 error 14
>>> qemu-dm[4963]: segfault at 0000000000000000 rip 0000000000000000 rsp
>>> 0000000040800198 error 14
>>>
>>
>> Thanks, I ever met this issue too, but did not pay much attention to
>> this :-(
>> Can you pls fire a bug?
>> -Xin
>>
>>> john.c
>>>
>>> - --
>>> John Clemens                        jclemens@xxxxxxxxxxxxxxx
>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxxxxxxxx
>>> http://lists.xensource.com/xen-devel
>>>
>>
>
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Attachment: ide_thread.patch
Description: ide_thread.patch

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