** Changed in: linux (Ubuntu) Status: In Progress => Fix Committed
** Tags removed: verification-needed-bionic ** Tags added: verification-done-bionic -- 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/1777338 Title: Linux 4.15.0-23 crashes during the boot process with a "Unable to handle kernel NULL pointer dereference" message Status in linux package in Ubuntu: Fix Committed Status in linux source package in Bionic: Fix Committed Bug description: == SRU Justification == Mainline commit 1f50ddb4f418 introduced a regression. That commit added speculative_store_bypass_ht_init() to the per-CPU initialization sequence. However, speculative_store_bypass_ht_init() needs to be called on each CPU for PV guests, as well. The regresssion prevents systems from booting. The patch to fix this regression has also been cc'd to upstream stable, but it has not landed in Bionic as of yet. == Fix == 74899d92e666 ("x86/xen: Add call of speculative_store_bypass_ht_init() to PV paths") == Regression Potential == Low. This patch fixes a current regressionThis patch has also been submitted to upstream stable, so it has had additional upstream review. == Test Case == A test kernel was built with this patch and tested by the original bug reporter. The bug reporter states the test kernel resolved the bug. I went to boot my computer today and it wouldn't boot. I get an "Unable to handle kernel NULL pointer dereference" message during the boot process, and, a bit after that, a message from the kernel watchdog about CPU #0 being stuck. Then the boot process stops completely. I was able to boot the system by telling Grub to load 4.15.0-22, which works perfectly fine, so there has been a regression. I am running Ubuntu as a Xen dom0, if that matters. I haven't tried booting the offending kernel version without Xen. I'm not sure where, if anywhere, these messages go on disk, for posting. ProblemType: Bug DistroRelease: Ubuntu 18.04 Package: linux-image-4.15.0-23-generic 4.15.0-23.25 ProcVersionSignature: Ubuntu 4.15.0-22.24-generic 4.15.17 Uname: Linux 4.15.0-22-generic x86_64 NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair ApportVersion: 2.20.9-0ubuntu7.1 Architecture: amd64 CurrentDesktop: ubuntu:GNOME Date: Sun Jun 17 10:12:58 2018 InstallationDate: Installed on 2017-08-06 (314 days ago) InstallationMedia: Ubuntu 17.04 "Zesty Zapus" - Release amd64 (20170412) ProcEnviron: TERM=xterm-256color PATH=(custom, no user) XDG_RUNTIME_DIR=<set> LANG=en_US.UTF-8 SHELL=/bin/bash SourcePackage: linux-signed UpgradeStatus: Upgraded to bionic on 2018-05-29 (19 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1777338/+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