On Wed, May 18, 2022 at 10:14 AM Brian Cowan <brcowan@xxxxxxxxx> wrote: > > Hi all, looking for hints on a wild crash. > > The company I work for has a kernel driver used to literally make a db > query result look like a filesystem… The “database” in question being > a proprietary SCM repository… (ClearCase, for those who have been > around forever… Like me…) > > We have a crash on mounting the remote repository ONE way (ClearCase > “Automatic views”) but not another (ClearCase “Dynamic views”) where > both use the same kernel driver… The guest OS is RHEL 7.8, not > registered with RH (since the VM is only supposed to last a couple of > days.) The host OS is Ubuntu 20.04.2 LTS, though that does not seem to > matter. > > The wild part is that this only happens when the ClearCase host is a > KVM guest, and only on 6th-generation or newer . It does NOT happen > on: > * VMWare Virtual machines configured identically > * VirtualBox Virtual machines Configured identically > * 2nd generation intel core hosts running the same KVM release. > (because OF COURSE my office "secondary desktop" host is ancient... > * A 4th generation I7 host running Ubuntu 22.04 and that version’s > default KVM. (Because I am a laptop packrat. That laptop had been > sitting on a bookshelf for 3+ years and I went "what if...") > > If I edit the KVM configuration and change the “mirror host CPU” > option to use the 2nd or 4th generation CPU options, the crash stops > happening… If this was happening on physical machines, the VM crash > would make sense, but it's literally a hypervisor-specific crash. > > Any hints, tips, or comments would be most appreciated... Never > thought I'd be trying to debug kernel/hypervisor interactions, but > here I am... Guest crash or hypervisor crash? If the former, can you provide the guest's console output?
