Re: [Xen-devel] dom0 linux 3.6.0-rc4, crash due to ballooning althoug dom0_mem=X, max:X set

[Ben Guthro <ben@xxxxxxxxxx>]

We ran into the same issue, in newer kernels - but had not yet
submitted this fix.

One of the developers here came up with a fix (attached, and CC'ed
here) that fixes an issue where the p2m code reuses a structure member
where it shouldn't.
The patch adds a new "old_mfn"  member to the gnttab_map_grant_ref
structure, instead of re-using  dev_bus_addr.


If this also works for you, I can re-submit it with a Signed-off-by
line, if you prefer, Konrad.

Ben


On Tue, Sep 4, 2012 at 1:19 PM, Sander Eikelenboom <linux@xxxxxxxxxxxxxx> wrote:
>
> Tuesday, September 4, 2012, 6:33:47 PM, you wrote:
>
>> On Tue, Sep 04, 2012 at 06:37:57PM +0200, Sander Eikelenboom wrote:
>>> Hi Konrad,
>>>
>>> This seems to happen only on a intel machine i'm trying to setup as a 
>>> development machine (haven't seen it on my amd).
>>> It boots fine, i have dom0_mem=1024M,max:1024M set, the machine has 2G of 
>>> mem.
>
>> Is this only with Xen 4.2? As, does Xen 4.1 work?
>>>
>>> Dom0 and guest kernel are 3.6.0-rc4 with config:
>
>> If you back out:
>
>> f393387d160211f60398d58463a7e65
>> Author: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
>> Date:   Fri Aug 17 16:43:28 2012 -0400
>
>>     xen/setup: Fix one-off error when adding for-balloon PFNs to the P2M.
>
>> Do you see this bug? (Either with Xen 4.1 or Xen 4.2)?
>
> With c96aae1f7f393387d160211f60398d58463a7e65 reverted i still see this bug 
> (with Xen 4.2).
>
> Will use the debug patch you mailed and send back the results ...
>
>
>>> [*] Xen memory balloon driver
>>> [*]   Scrub pages before returning them to system
>>>
>>> From 
>>> http://wiki.xen.org/wiki/Do%EF%BB%BFm0_Memory_%E2%80%94_Where_It_Has_Not_Gone
>>>  , I thought this should be okay
>>>
>>> But when trying to start a PV guest with 512MB mem, the machine (dom0) 
>>> crashes with the stacktrace below (complete serial-log.txt attached).
>>>
>>> From the:
>>> "mapping kernel into physical memory
>>> about to get started..."
>>>
>>> I would almost say it's trying to reload dom0 ?
>>>
>>>
>>> [  897.161119] device vif1.0 entered promiscuous mode
>>> mapping kernel into physical memory
>>> about to get started...
>>> [  897.696619] xen_bridge: port 1(vif1.0) entered forwarding state
>>> [  897.716219] xen_bridge: port 1(vif1.0) entered forwarding state
>>> [  898.129465] ------------[ cut here ]------------
>>> [  898.132209] kernel BUG at drivers/xen/balloon.c:359!
>>> [  898.132209] invalid opcode: 0000 [#1] PREEMPT SMP
>
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxx
> http://lists.xen.org/xen-devel

Attachment: gnttab_old_mfn
Description: Binary data

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel