Important additional reproduction: I have now reproduced the same issue on a completely different physical host.
Second host: - Intel Core i9-12900K (Alder Lake) - Ubuntu 26.04.1 host - Host kernel: 7.0.0-30-generic I installed a fresh Ubuntu 26.04.1 LTS VM on this host using the same host-passthrough / migratable='off' CPU configuration. The new VM reproduced the same failure, including: Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000008b This is particularly notable because this second host has been running older VMs with migratable='off' reliably for years. Therefore: - The issue is reproducible on both Intel Core i5-14400 (Raptor Lake Refresh) and Intel Core i9-12900K (Alder Lake). - It is reproducible with host kernel 7.0.0-30 as well as 7.0.0-31. - This makes a hardware-specific fault on the i5-14400 system much less likely. - It also rules out a regression specific to host kernel 7.0.0-31. - Older VMs on the i9-12900K host remain stable with migratable='off', while a newly installed Ubuntu 26.04.1 LTS VM reproduces the problem. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/2166603 Title: KVM guests randomly panic/freeze with host-passthrough migratable=off, stable with migratable=on To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2166603/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
