** Description changed: + [Impact] + The kdump kernel will crash during its boot if booted on a CPU other than 0. + + [Test case] + Trigger a crash using taskset -c X, where X is not 0 and is a present CPU. Check that the dump is successful. + + [Regression potential] + This will cause more memory to be used by the dump kernel, which may cause OOMs during the dump. The fix is restricted to ppc64el. + + == Comment: #0 - Hari Krishna Bathini - 2019-05-10 06:38:21 == ---Problem Description--- - kdump boots fails in some environments when nr_cpus=1 is passed - + kdump boots fails in some environments when nr_cpus=1 is passed + ---uname output--- na - - Machine Type = na - + + Machine Type = na + ---Debugger--- A debugger is not configured - + ---Steps to Reproduce--- - 1. configure kdump + 1. configure kdump 2. trigger crash on non-boot cpu Expected result: Capture dump and reboot Actual result: Hang in early kdump boot process after crash - - Userspace tool common name: kdump-tools - - The userspace tool has the following bit modes: 64-bit + + Userspace tool common name: kdump-tools + + The userspace tool has the following bit modes: 64-bit Userspace rpm: kdump-tools Userspace tool obtained from project website: na == Comment: #1 - Hari Krishna Bathini - 2019-05-10 06:45:46 == Launchpad bug 1560552 added "nr_cpus=1" support on ppc64 though this change never made it upstream as maintainer has a few apprehensions.. With 4.18 kernels, this change is dropped on Ubuntu kernels too. With nr_cpus=1 support in kernel, kdump-tools was also updated to use "nr_cpsu=1" by default instead of "maxcpus=1" (see launchpad bug 1568952). This kdump-tools change has to be reverted to make it consist with the kernel change. Note that "nr_cpus=1 change had a issues in kdump guest environment even with "nr_cpus=1" support for kdump in kernel. So, even not withstanding the kernel revert, it is better to default to "maxcpus=1" on all kernel versions. So, please revert the kdump-tools fix that went in with launchpad bug 1568952
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1828597 Title: KDump boot fails with nr_cpus=1 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu-power-systems/+bug/1828597/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
