Capturing a kernel dump may fail if hugepages are enabled in /etc/sysctl.conf

This document (7017830) is provided subject to the disclaimer at the end of this document.

Environment

SUSE Linux Enterprise Server 11 Service Pack 1 (SLES 11 SP1)
SUSE Linux Enterprise Server 11 Service Pack 2 (SLES 11 SP2)
SUSE Linux Enterprise Server 11 Service Pack 3 (SLES 11 SP3)
SUSE Linux Enterprise Server 11 Service Pack 4 (SLES 11 SP4)
SUSE Linux Enterprise Server 12 Service Pack 1 (SLES 12 SP1)

Situation

With kdump-0.8.15-21.1, capturing a kernel dump will fail if the kernel tuneable nr_hugepages is enabled in /etc/sysctl.conf.
If there is an entry like

p, li { white-space: pre-wrap; }

vm.nr_hugepages=YYY

where YYY is the amount of huge pages to be enabled.

Resolution

A workaround would be to remove the line for the hugepages in /etc/sysctl.conf and
add it to the kernel commandline instead.

The best approach to modify the kernel commandline is to start:

yast2 bootloader, switch to the "Kernel Parameters" Tab and add the following parameter:
hugepages=XXX

in the line "Optional Kernel Command Line Parameter" (for SLES12)

where XXX is the requested number of hugepages to be enabled.
After the file had been saved you need to run "mkdumprd"
to create a new initrd for the kdump kernel.
hugepages=360 p, li { white-space: pre-wrap; }hugepages=360

Cause

Enabled hugepages will cause the capture kernel to run into an
out of memory (OOM) condition, preventing it to start the scripts
responsible to save the kernel dump.

Disclaimer

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