I've only been able to reproduce this on systems with an Intel IOMMU. Disabling the IOMMU in the firmware (usually labelled "VT-d") lets the latest 4.13 i386 kernel boot. It's also reproducible in qemu if you give it an IOMMU, eg. "-machine q35 -device intel-iommu".
The problem is that the IDT page (0xffc00000) overlaps the FIX_BTMAPS range. IOMMU detection tries to read ACPI tables, which eventually calls early_ioremap, which maps an ACPI table over the IDT, and then eventually unmaps it completely. The first kernel interrupt after that (usually in test_wp_bit) triple-faults when it can't find the IDT. I've built an experimental kernel with the FIX_BTMAPS vs IDT conflict fixed at https://people.canonical.com/~wgrant/linux- image-4.13.0-31-generic_4.13.0-31.34~16.04.1_i386.deb. It works on my affected hardware and qemu, but it would be good to confirm that it's the same issue that others have. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1745118 Title: Unable to boot with i386 4.13.0-25 / 4.13.0-26 / 4.13.0-31 kernel on Xenial / Artful To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1745118/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
