------- Comment From hbath...@in.ibm.com 2019-05-22 02:33 EDT------- (In reply to comment #11) > Hi, Hari. > > So, as you said, other architectures will use add/remove instead of online, > and we want to support them too. Any reason not to do it that you are > thinking of?
No action with these rules on ppc64 as ADD/REMOVE events are not ejected for CPU subsystem as of today. So, they don't have any impact and can be ignored. But I thought this rules were there by accident and the entries would be put under arch flags to avoid them for ppc64.. -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to kexec-tools in Ubuntu. https://bugs.launchpad.net/bugs/1828596 Title: kdump fails when crash is triggered after DLPAR cpu add operation Status in The Ubuntu-power-systems project: Incomplete Status in kexec-tools package in Ubuntu: Invalid Status in makedumpfile package in Ubuntu: Incomplete Bug description: == Comment: #0 - Hari Krishna Bathini - 2019-05-10 05:55:40 == ---Problem Description--- kdump fails when crash is triggered after CPU add operation. Machine Type = na ---System Hang--- Crashed in early boot process of kdump kernel after crash Had to issue system reset from HMC to reclaim ---Steps to Reproduce--- 1. Configure kdump. 2. Add cpu from HMC. 3. Trigger crash. 4. Machine hangs after crash as below: --- [169250.213166] IPI complete [169250.234331] kexec: Starting switchover sequence. I'm in purgatory --- STRUCK HERE --- ---uname output--- na ---Debugger--- A debugger is not configured == Comment: #1 - Hari Krishna Bathini - 2019-05-10 05:56:46 == The problem is, kexec udev rule to restart kdump-tools service - when a core is added, is not being triggered. The old DT created by kexec (before the core is added) is being used by KDump Kernel. So, when system crashes on a thread from the added core(s), KDump kernel is failing to get the 'boot_cpuid' and eventually failing to boot.. == Comment: #2 - Hari Krishna Bathini - 2019-05-10 06:02:27 == The udev rule when CPU is added is not triggered because ppc64 does not eject add/remove event when a CPU is hot added/removed. It only ejects online/offline event to user space when CPU is hot added/removed. So, the below udev rules are never triggered when needed: SUBSYSTEM=="cpu", ACTION=="add", PROGRAM="/bin/systemctl try-restart kdump-tools.service" SUBSYSTEM=="cpu", ACTION=="remove", PROGRAM="/bin/systemctl try-restart kdump-tools.service" Also, with how CPU hot add & remove are handled in ppc64, a udev trigger to reload kdump after CPU is hot removed is NOT necessary. So, fix the CPU hot add case by updating the udev rule and drop the udev rule meant for CPU hot remove in the kdump udev rules file: SUBSYSTEM=="cpu", ACTION=="online", PROGRAM="/bin/systemctl try-restart kdump-tools.service" To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1828596/+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