Comment 0 for bug 1828597

bugproxy (bugproxy) wrote :

== 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

---uname output---
na

Machine Type = na

---Debugger---
A debugger is not configured

---Steps to Reproduce---
 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 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