[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Xen 4.0.0x allows for data corruption in Dom0
On 03/09/2010 12:41 AM, Jeremy Fitzhardinge wrote: > On 03/08/2010 03:23 PM, Joanna Rutkowska wrote: >> But the corruptions always happen in 32-bytes chunks, which might >> suggest it's not a page-related problem (e.g. wrongly re-used page), as >> in that case we would be observing (at least sometimes) much bigger >> chunks of corrupted data, I think. >> > > Given that the domU doesn't have any devices or much going on, it could > easily be corrupting memory in only small amounts. > But see, before I tried this with such a small dummy do-nothing DomU (which I did for the purpose of reporting to xen-devel), I experienced very similar corruption when running regular VMs, i.e. with normal linux and all the usual apps inside them. Same pattern of corruption. >> The reason why I still believe it's a hypervisor related thing, it that >> I'm currently using the very *same* Dom0 kernel (very recent >> xen/stable-2.6.31) with Xen 3.4.2 and the system is damn stable. And I >> really mean extensive use with 5-7 VMs running all the time doing >> various things from Web browsing to kernel building. >> > > OK, it's always good to get some positive feedback. > At least one full-time user of the pvops kernel ;) >> If I was to make an educated guess I would say it's something related to >> some interrupt handling, i.e. Xen mishandling it, e.g. the handler is >> writing out-of-buffer somewhere and it just happens to land in the Dom0 >> fs buffer used by e.g. dd operation. >> > > > It would be interesting to see what happens if you write the file with > the test domain paused (xm pause ...). If the corruption continues, > then it is almost certainly Xen. Right. > If it stops, then it either means the > corruption was caused by pages inappropriately shared between dom0 and > domU, or something like vcpu context switch is corrupting memory (which > would be very sad). > Unfortunately, I cannot do any more tests. We have downgraded all our test machines to Xen 3.4.2 and are using them for other things now. Sorry. joanna. Attachment:
signature.asc _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
|
![]() |
Lists.xenproject.org is hosted with RackSpace, monitoring our |