Hello. I apologize for not testing the latest v4.16 kernel, but I've decided to wait for an update to the v4.4 kernel used in "Xenial". And it seems, that everything is okay now and 'kaslr' option is working again. After update Linux kernel to the v4.4.0-117-generic (v4.4.114) version, system boots normally. I've done some tests:
● boot system via GRUB (add 'kaslr' option and press 'CTRL + X') ● edit '/etc/default/grub' file and add 'kaslr' option to the 'GRUB_CMDLINE_LINUX_DEFAULT=' Everything is fine, system starts normally etc. There is no problem, as I've described in my post #4. So, some of the patches (see 1.) fixed this issue. Thanks, best regards. _____________________ 1. https://git.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/xenial/commit/?id=fc74a5c4a98418105b4b246b935e3be90d6a635c ** Tags added: kernel-fixed-upstream ** Changed in: linux (Ubuntu) Status: Incomplete => Confirmed ** Changed in: linux (Ubuntu Xenial) Status: Incomplete => Confirmed -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1748710 Title: Linux 4.4.0-113.136 (i386/x86_32): failed to boot and BusyBox v1.22.1 built-in shell (initramfs). Status in linux package in Ubuntu: Confirmed Status in linux source package in Xenial: Confirmed Bug description: Hello. On Thu Feb 8, Linux kernel for Ubuntu 16.04.3 LTS has been updated to the 4.4.0-113.136 version (xenial-proposed). However, after reboot, plymouth freezes during start, and keys on an USB keyboard were in- active. After several seconds, the BusyBox shell screen appeared. It looks this way: ,------ | BusyBox v1.22.1 (Ubuntu 1:1.22.0-15ubuntu1) built-in shell (ash) | Enter 'help' for a list of built-in commands. | | (initramfs) _ `------ Unfortunately, the USB keyboard does not work and does not respond. The only way to solve this issue is a "hard reset" and in GRUB menu choosing an earlier kernel, which is linux 4.4.0-112.135. Now, everything works okay. Proposed update to the Linux 4.4.0-113.136 contains many new updates (please see 1.) It's an i386/x86_32 architecture, which does not contain PTI yet, right? I'm asking, because mentioned -proposed updates contains a couple of PTI-related patches and bugs in PTI can cause a few different signatures of crashes etc. For example: → Crashes in early boot, especially around CPU bringup. Bugs in the trampoline code or mappings cause these. → Userspace segfaults early in boot, sometimes manifesting as mount(8) failing to mount the rootfs. These have tended to be TLB invalidation issues. Usually invalidating the wrong PCID, or otherwise missing an invalidation. NOTE: if it's about PCID, which is mentioned in a second point, there is one patch in -proposed update: "x86/mm/32: Move setup_clear_cpu_cap(X86_FEATURE_PCID) earlier". Maybe that's is the cause of a boot failure? There are no errors in log files, such as '/var/log/syslog' or '/var/log/kern.log'. However, it's a Celeron, "E" series. So, I don't know if mentioned patches are good for this type of processor etc.? Especially on i386/x86_32 architecture. ● UPDATE/WARNING: It seems, that 'kaslr' option is responsible for this issue. After booting the latest v4.4.0-115.139 kernel, I've had the same problems as described above. However, after removing 'kaslr' option from a command line via GRUB menu, system started normally etc. The latest, working kernel with 'kaslr' option is v4.4.0-112.135. According to all of this I think, that 'kaslr' is not compatible with some "Spectre & Meltdown" mitigation patches and fixes etc. ✗ Release ('/proc/version_signature'): Ubuntu 4.4.0-112.135-generic 4.4.98 ✗ Architecture: i386/x86_32 ✗ PCI ('lspci -vnvn'): 00:0a.0 PCI bridge [0604]: NVIDIA Corporation MCP73 PCI Express bridge [10de:056d] (rev a1) (prog-if 01 [Subtractive decode]) Capabilities: [b8] Subsystem: Gigabyte Technology Co., Ltd MCP73 PCI Express bridge [1458:026f] Thanks, regards. ________________ 1. https://lists.ubuntu.com/archives/xenial- changes/2018-February/020108.html To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1748710/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp
