Messages in this thread | | | Date | Wed, 04 Jun 2008 16:42:50 +0300 | From | Avi Kivity <> | Subject | Re: kvm causing memory corruption? now 2.6.26-rc4 |
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Dave Hansen wrote: > On Thu, 2008-03-27 at 16:59 +0200, Avi Kivity wrote: > >> Dave Hansen wrote: >> >>> On Thu, 2008-03-27 at 12:10 +0200, Avi Kivity wrote: >>> >>>> btw, is this with >= 4GB RAM on the host? >>>> >>> Well, are you asking whether I have PAE on or not? :) >>> >> No, I'm asking whether there is a possibility of address truncation :) >> >> PAE by itself doesn't affect kvm much, as it always runs the guest in >> pae mode. >> >> Can you try running with mem=2000M or something? >> > > I have a few more data points on this. Sorry for the massive delay from > the last report -- I'm being a crappy bug reporter. But, this is on my > one and only laptop which makes it a serious pain to diagnose. I also > didn't have a hardware serial console on it before, which I do now. > This is all on 2.6.26-rc4-01549-g1beee8d. > > Adding the mem= does not help at all. But, it is all a bit more > diagnosable now than a month or two ago. I turned on all of the kernel > debugging that I could get my grubby little hands on. It now oopses > quite consistently when kvm runs instead of after. Here's a collection > of oopses that I captured after setting up a serial line: > > http://sr71.net/~dave/kvm-oops1.txt > > After collecting all those, I turned on CONFIG_DEBUG_HIGHMEM and the > oopses miraculously stopped. But, the guest hung (for at least 5 > minutes or so) during windows bootup, pegging my host CPU. Most of the > CPU was going to klogd, so I checked dmesg. > >
Can you check with mem=900 (and CONFIG_HIGHMEM_DEBUG=n)? That will confirm that the problems are highmem related, but not physical address truncation related.
> I was seeing messages like this > > [ 428.918108] kvm_handle_exit: unexpected, valid vectoring info and exit reason is 0x9 > > And quite a few of them, like 100,000/sec. That's why klogd was pegging > the CPU. Any idea on a next debugging step? > >
That's a task switch. Newer kvms handle them.
-- Do not meddle in the internals of kernels, for they are subtle and quick to panic.
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