** Description changed: + SRU Justification: + ================== + + [ Impact ] + + * Ubuntu 18.04 / bionic installations with latest kernel 4.15.0-194 + are no longer able to IPL (boot) on IBM z14 or newer hardware. + + * This issue got introduced by upstream commit e4f74400308c + "s390/archrandom: simplify back to earlier design and initialize earlier" + that was SRUed to 18.04/bionic based on LP#1989625, + which made changes in the s390s IPL/boot area of kernel/arch/random. + + * The reason seems to be that the bad patch moves the decision about + if arch randomness is available to setup.c function setup_randomness(). + This code uses a static_key s390_arch_random_available. + But in the Canonical kernel the initialization function + for the jump labels (where the static keys are based on) + jump_label_init() is called in generic start_kernel() + wheres in the upstream kernel the init function is + called early in setup_arch(). + + * Reverting this commit from bionic master-next makes bionic systems + again bootable. + (https://launchpad.net/~fheimes/+archive/ubuntu/test/) + + [ Test Plan ] + + * An IBM z14 or LinuxONE II or newer system is needed. + + * Now install latest bionic on that system - doesn't if it's on LPAR, + z/VM or KVM. + + * After the installation (an the trigger of the post install reboot), + the system will not come up. + + * To test a patched kernel with e4f74400308c can be tested in the + following way: + + * Install 18.04 GA and prevent it from doing any kernel updates. + + * Means, install in 'island' mode + or select in d-i 'Advanced Installation' + and explicitly choose '4.15.0-50 generic' to install. + + * That allows the system to come up and to update the kernel to + a modified one. + + * Then reboot and verify if the system comes up properly. + + [ Where problems could occur ] + + * Problems could occur due to the fact that the commit + was not cleanly reversible because of minor context changes. + + * Adjustments that were needed might break other things if not + done carefully. + + * Further commits (applied after e4f74400308c) may still rely + on the bad e4f74400308c commit - or even further patches + (from upstream stable). + + * In worst case IPL / boot might get broken, + even on hardware older than z14. + + * If the revert works fine can be easily tested and was tested based on + https://launchpad.net/~fheimes/+archive/ubuntu/test/ + and the above test plan. + + [ Other Info ] + + * Ubuntu 20.04 (focal, using legacy image with virt-install) + was tested as well, but is not affected by this issue. + __________ + ---Problem Description--- Ubuntu 18.04 crashes during IPL with no output on the console. - - Contact Information = Viktor Mihajlovski <mihaj...@de.ibm.com> - + Contact Information = Viktor Mihajlovski <mihaj...@de.ibm.com> + ---uname output--- n/a - - Machine Type = 3096 - + + Machine Type = 3096 + ---Debugger--- A debugger is not configured - + ---Steps to Reproduce--- - Install Ubuntu 18.04 as a KVM guest using the following command: + Install Ubuntu 18.04 as a KVM guest using the following command: virt-install -n bionic --cdrom /var/lib/libvirt/images/ubuntu-18.04.5-server-s390x.iso --memory 2048 --disk size=8 then reboot. - + Stack trace output: - no - + no + Oops output: - no + no == Comment: #1 - Viktor Mihajlovski <mihaj...@de.ibm.com> - 2022-10-25 10:48:30 == Installing under z/VM leads to the same failure. == Comment: #2 - Viktor Mihajlovski <mihaj...@de.ibm.com> - 2022-10-25 10:55:10 == I have captured a dump using virsh dump --memory-only. The output of crash log is uploaded == Comment: #7 - Harald Freudenberger <fre...@de.ibm.com> - 2022-10-26 07:33:52 == Looks like all ubuntu 18.04 installations on s390 are not working any more. It is not an issue with z14 but z17 also fails to run a fresh installed ubuntu 18.04. == Comment: #8 - Harald Freudenberger <fre...@de.ibm.com> - 2022-10-26 08:25:52 == when I use the 'advanced installation' where I am able to choose the kernel package and then choose the 4.15.0-50 generic the installed Ubuntu 18.04 comes up fine. So this issue is somewhere between kernel 4.15.0-50 and 4.15.0-194.
-- 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/1994601 Title: [UBUNTU 18.04] Ubuntu 18.04 kernel 4.15.0-194 crashes on IPL Status in Ubuntu on IBM z Systems: Confirmed Status in linux package in Ubuntu: Confirmed Bug description: SRU Justification: ================== [ Impact ] * Ubuntu 18.04 / bionic installations with latest kernel 4.15.0-194 are no longer able to IPL (boot) on IBM z14 or newer hardware. * This issue got introduced by upstream commit e4f74400308c "s390/archrandom: simplify back to earlier design and initialize earlier" that was SRUed to 18.04/bionic based on LP#1989625, which made changes in the s390s IPL/boot area of kernel/arch/random. * The reason seems to be that the bad patch moves the decision about if arch randomness is available to setup.c function setup_randomness(). This code uses a static_key s390_arch_random_available. But in the Canonical kernel the initialization function for the jump labels (where the static keys are based on) jump_label_init() is called in generic start_kernel() wheres in the upstream kernel the init function is called early in setup_arch(). * Reverting this commit from bionic master-next makes bionic systems again bootable. (https://launchpad.net/~fheimes/+archive/ubuntu/test/) [ Test Plan ] * An IBM z14 or LinuxONE II or newer system is needed. * Now install latest bionic on that system - doesn't if it's on LPAR, z/VM or KVM. * After the installation (an the trigger of the post install reboot), the system will not come up. * To test a patched kernel with e4f74400308c can be tested in the following way: * Install 18.04 GA and prevent it from doing any kernel updates. * Means, install in 'island' mode or select in d-i 'Advanced Installation' and explicitly choose '4.15.0-50 generic' to install. * That allows the system to come up and to update the kernel to a modified one. * Then reboot and verify if the system comes up properly. [ Where problems could occur ] * Problems could occur due to the fact that the commit was not cleanly reversible because of minor context changes. * Adjustments that were needed might break other things if not done carefully. * Further commits (applied after e4f74400308c) may still rely on the bad e4f74400308c commit - or even further patches (from upstream stable). * In worst case IPL / boot might get broken, even on hardware older than z14. * If the revert works fine can be easily tested and was tested based on https://launchpad.net/~fheimes/+archive/ubuntu/test/ and the above test plan. [ Other Info ] * Ubuntu 20.04 (focal, using legacy image with virt-install) was tested as well, but is not affected by this issue. __________ ---Problem Description--- Ubuntu 18.04 crashes during IPL with no output on the console. Contact Information = Viktor Mihajlovski <mihaj...@de.ibm.com> ---uname output--- n/a Machine Type = 3096 ---Debugger--- A debugger is not configured ---Steps to Reproduce--- Install Ubuntu 18.04 as a KVM guest using the following command: virt-install -n bionic --cdrom /var/lib/libvirt/images/ubuntu-18.04.5-server-s390x.iso --memory 2048 --disk size=8 then reboot. Stack trace output: no Oops output: no == Comment: #1 - Viktor Mihajlovski <mihaj...@de.ibm.com> - 2022-10-25 10:48:30 == Installing under z/VM leads to the same failure. == Comment: #2 - Viktor Mihajlovski <mihaj...@de.ibm.com> - 2022-10-25 10:55:10 == I have captured a dump using virsh dump --memory-only. The output of crash log is uploaded == Comment: #7 - Harald Freudenberger <fre...@de.ibm.com> - 2022-10-26 07:33:52 == Looks like all ubuntu 18.04 installations on s390 are not working any more. It is not an issue with z14 but z17 also fails to run a fresh installed ubuntu 18.04. == Comment: #8 - Harald Freudenberger <fre...@de.ibm.com> - 2022-10-26 08:25:52 == when I use the 'advanced installation' where I am able to choose the kernel package and then choose the 4.15.0-50 generic the installed Ubuntu 18.04 comes up fine. So this issue is somewhere between kernel 4.15.0-50 and 4.15.0-194. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1994601/+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
