------- Comment From peter.oberparlei...@de.ibm.com 2016-07-14 08:43 EDT------- As an alternate solution, try this:
1) Modify /usr/share/initramfs-tools/scripts/init-top/udev Replace line udevadm trigger --action=add with udevadm trigger --type=subsystems --action=add udevadm trigger --type=devices --action=add 2) Modify /etc/default/kdump-tools Replace existing KDUMP_CMDLINE_APPEND= lines with KDUMP_CMDLINE_APPEND="cio_ignore=all,!condev" 3) Rebuild the kdump initramfs /etc/kernel/postinst.d/kdump-tools 4) Check if kdump works echo c > /proc/sysrq-trigger Explanation: - Ubuntu 16.04 uses zdev to configure z Systems specific devices - zdev also handles cio_ignore configuration via a Udev rule that triggers when the CCW bus is registered (see /etc/udev/rules.d/41-cio-ignore.rules) - Because of the way that Ubuntu's initramfs tools trigger coldplug of Uevents, the Uevent for the CCW bus is not generated and the cio_ignore rule is not triggered. I consider this a bug in Ubuntu's udev package because systemd provides a corresponding coldplug unit file (see /lib/systemd/system/systemd-udev-trigger.service) that performs the steps as proposed in 1) - With cio_ignore handling covered by the udev rule, KDUMP can use the command line in 2) to blacklist all devices except the console. The latter needs to be excluded as the kernel would otherwise not boot on a z/VM guest -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to makedumpfile in Ubuntu. https://bugs.launchpad.net/bugs/1570775 Title: makekdump should re-exec with cio_ignore on s390x Status in Ubuntu on IBM z Systems: Fix Released Status in makedumpfile package in Ubuntu: Fix Released Status in makedumpfile source package in Xenial: In Progress Bug description: As per https://bugs.launchpad.net/ubuntu/+source/makedumpfile/+bug/1564475/comments/19 We should re-exec with cio_ignore lines. As per report there, it should result in lowered required crashdump setting. Hypothetically, one should be able to test this imperially by lowering crashdump memory settings until kdump does not succeed anymore. And then generated and append `cio_ignore -k -u` to the KDUMP_CMDLINE_APPEND= and see that kdump starts working again with a lower memory usage. Once this is developed / verified / tested, we should probably SRU this back to xenial. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-z-systems/+bug/1570775/+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
