# makedumpfile -v
makedumpfile: version 1.7.7 (released on 21 Apr 2025)
lzo enabled
snappy enabled
zstd disabled
cd /root/
# makedumpfile -v
makedumpfile: version 1.7.7 (released on 21 Apr 2025)
lzo enabled
snappy enabled
zstd disabled
# systemctl stop kdump.service
# systemctl start kdump.service
systemctl status kdump.service --no-pager
● kdump.service - Crash recovery kernel arming
Loaded: loaded (/usr/lib/systemd/system/kdump.service; enabled;
preset: enabled)
Active: active (exited) since Fri 2026-01-09 09:12:01 CST; 7s ago
Process: 2071 ExecStart=/usr/bin/kdumpctl start (code=exited,
status=0/SUCCESS)
Main PID: 2071 (code=exited, status=0/SUCCESS)
CPU: 41.857s
Jan 09 09:11:55 ltcden8-lp5.ltc.tadn.ibm.com dracut[2839]: *** Install
squash…**
Jan 09 09:11:56 ltcden8-lp5.ltc.tadn.ibm.com dracut[2839]: ***
Stripping file…**
Jan 09 09:11:56 ltcden8-lp5.ltc.tadn.ibm.com dracut[2839]: ***
Stripping file…**
Jan 09 09:11:56 ltcden8-lp5.ltc.tadn.ibm.com dracut[2839]: ***
Squashing the …**
Jan 09 09:11:58 ltcden8-lp5.ltc.tadn.ibm.com dracut[2839]: ***
Squashing the …**
Jan 09 09:11:58 ltcden8-lp5.ltc.tadn.ibm.com dracut[2839]: ***
Creating image…**
Jan 09 09:11:58 ltcden8-lp5.ltc.tadn.ibm.com dracut[2839]: ***
Creating initr…**
Jan 09 09:12:01 ltcden8-lp5.ltc.tadn.ibm.com kdumpctl[2074]: kdump:
kexec: lo…el
Jan 09 09:12:01 ltcden8-lp5.ltc.tadn.ibm.com kdumpctl[2074]: kdump:
Starting …K]
Jan 09 09:12:01 ltcden8-lp5.ltc.tadn.ibm.com systemd[1]: Finished
Crash recov…g.
Hint: Some lines were ellipsized, use -l to show in full.
# echo 10 > /proc/sys/kernel/panic
# echo 1 > /proc/sys/kernel/sysrq
# echo c > /proc/sysrq-trigger
[ 595.605706] sysrq: Trigger a crash
[ 595.605721] Kernel panic - not syncing: sysrq triggered crash
[ 595.605729] CPU: 0 UID: 0 PID: 1840 Comm: bash Kdump: loaded Not
tainted 6.17.0 #6 VOLUNTARY
[ 595.605739] Hardware name: IBM,9080-HEX Power11 (architected)
0x820200 0xf000007 of:IBM,FW1110.01 (NH1110_069) hv:phyp pSeries
[ 595.605747] Call Trace:
[ 595.605752] [c0000000a0e17920] [c00000000184c0e8]
dump_stack_lvl+0xd0/0xe8 (unreliable)
[ 595.605769] [c0000000a0e17950] [c0000000001b2434] vpanic+0x498/0x518
[ 595.605781] [c0000000a0e17a00] [c0000000001b2504] nmi_panic+0x0/0x13c
[ 595.605791] [c0000000a0e17a20] [c000000000e95d8c]
sysrq_handle_crash+0x30/0x34
[ 595.605804] [c0000000a0e17a80] [c000000000e96c98]
__handle_sysrq+0x124/0x384
[ 595.605814] [c0000000a0e17b40] [c000000000e97a9c]
write_sysrq_trigger+0x184/0x228
[ 595.605826] [c0000000a0e17bc0] [c0000000009f1c54]
proc_reg_write+0x18c/0x240
[ 595.605838] [c0000000a0e17c10] [c000000000896588]
vfs_write+0x148/0x7d8
[ 595.605848] [c0000000a0e17cf0] [c000000000896eb4]
ksys_write+0xa0/0x184
[ 595.605858] [c0000000a0e17d50] [c0000000000393d0]
system_call_exception+0x1e0/0x460
[ 595.605869] [c0000000a0e17e50] [c00000000000d05c]
system_call_vectored_common+0x15c/0x2ec
[ 595.605882] ---- interrupt: 3000 at 0x7fff9ab33e74
[ 595.605890] NIP: 00007fff9ab33e74 LR: 00007fff9ab33e74 CTR:
0000000000000000
[ 595.605897] REGS: c0000000a0e17e80 TRAP: 3000 Not tainted (6.17.0)
[ 595.605904] MSR: 800000000280f033
<SF,VEC,VSX,EE,PR,FP,ME,IR,DR,RI,LE> CR: 44422408 XER: 00000000
[ 595.605936] IRQMASK: 0
[ 595.605936] GPR00: 0000000000000004 00007fffc3c7fab0
0000000135727e00 0000000000000001
[ 595.605936] GPR04: 000000014b93c040 0000000000000002
0000000000000010 0000000000000001
[ 595.605936] GPR08: 0000000000000001 0000000000000000
0000000000000000 0000000000000000
[ 595.605936] GPR12: 0000000000000000 00007fff9adfab60
000000014b9fc1d0 00000001357287b8
[ 595.605936] GPR16: 00000001357294d8 0000000020000000
0000000000000000 0000000135639070
[ 595.605936] GPR20: 00000001356cbeb8 00007fffc3c7fc54
00000001356cf8a0 00000001357289bc
[ 595.605936] GPR24: 0000000135728a50 0000000000000000
000000014b93c040 0000000000000002
[ 595.605936] GPR28: 0000000000000002 00007fff9ac318e0
000000014b93c040 0000000000000002
[ 595.606034] NIP [00007fff9ab33e74] 0x7fff9ab33e74
[ 595.606040] LR [00007fff9ab33e74] 0x7fff9ab33e74
[ 595.606046] ---- interrupt: 3000
8:41
# cat /etc/kdump.conf
# This file contains a series of commands to perform (in order) in the
kdump
# kernel after a kernel crash in the crash kernel(1st kernel) has
happened.
#
# Directives in this file are only applicable to the kdump initramfs,
and have
# no effect once the root filesystem is mounted and the normal init
scripts are
# processed.
#
# Currently, only one dump target and path can be specified. If the
dumping to
# the configured target fails, the failure action which can be
configured via
# the "failure_action" directive will be performed.
#
# Supported options:
#
# auto_reset_crashkernel <yes|no>
# - whether to reset kernel crashkernel to new default value
# or not when kexec-tools updates the default crashkernel
value and
# existing kernels using the old default kernel
crashkernel value.
# The default value is yes.
#
# raw <partition>
# - Will dd /proc/vmcore into <partition>.
# Use persistent device names for partition devices,
# such as /dev/vg/<devname>.
#
# nfs <nfs mount>
# - Will mount nfs to <mnt>, and copy /proc/vmcore to
# <mnt>/<path>/%HOST-%DATE/, supports DNS.
#
# ssh <user@server>
# - Will save /proc/vmcore to
<user@server>:<path>/%HOST-%DATE/,
# supports DNS.
# NOTE: make sure the user has write permissions on the
server.
#
# sshkey <path>
# - Will use the sshkey to do ssh dump.
# Specify the path of the ssh key to use when dumping
# via ssh. The default value is /root/.ssh/kdump_id_rsa.
#
# <fs type> <partition>
# - Will mount -t <fs type> <partition> <mnt>, and copy
# /proc/vmcore to <mnt>/<path>/%HOST_IP-%DATE/.
# NOTE: <partition> can be a device node, label or uuid.
# It's recommended to use persistent device names
# such as /dev/vg/<devname>.
# Otherwise it's suggested to use label or uuid.
# Supported fs types: ext[234], xfs, btrfs, minix, virtiofs
#
# path <path>
# - "path" represents the file system path in which vmcore
# will be saved. If a dump target is specified in
# kdump.conf, then "path" is relative to the specified
# dump target.
#
# Interpretation of "path" changes a bit if the user didn't
# specify any dump target explicitly in kdump.conf. In this
# case, "path" represents the absolute path from root. The
# dump target and adjusted path are arrived at automatically
# depending on what's mounted in the current system.
#
# Ignored for raw device dumps. If unset, will use the
default
# "/var/crash".
#
# core_collector <command> <options>
# - This allows you to specify the command to copy
# the vmcore. The default is makedumpfile, which on
# some architectures can drastically reduce vmcore size.
# See /sbin/makedumpfile --help for a list of options.
# Note that the -i and -g options are not needed here,
# as the initrd will automatically be populated with a
# config file appropriate for the running kernel.
# The default core_collector for raw/ssh dump is:
# "makedumpfile -F -l --message-level 7 -d 31".
# The default core_collector for other targets is:
# "makedumpfile -l --message-level 7 -d 31".
#
# "makedumpfile -F" will create a flattened vmcore.
# You need to use "makedumpfile -R" to rearrange the dump
data to
# a normal dumpfile readable with analysis tools. For
example:
# "makedumpfile -R vmcore < vmcore.flat".
#
# For core_collector format details, you can refer to
# kexec-kdump-howto.txt or kdump.conf manpage.
#
# kdump_post <binary | script>
# - This directive allows you to run a executable binary
# or script after the vmcore dump process terminates.
# The exit status of the current dump process is fed to
# the executable binary or script as its first argument.
# All files under /etc/kdump/post.d are collectively sorted
# and executed in lexical order, before binary or script
# specified kdump_post parameter is executed.
#
# kdump_pre <binary | script>
# - Works like the "kdump_post" directive, but instead of
running
# after the dump process, runs immediately before it.
# Exit status of this binary is interpreted as follows:
# 0 - continue with dump process as usual
# non 0 - run the final action (reboot/poweroff/halt)
# All files under /etc/kdump/pre.d are collectively sorted
and
# executed in lexical order, after binary or script specified
# kdump_pre parameter is executed.
# Even if the binary or script in /etc/kdump/pre.d directory
# returns non 0 exit status, the processing is continued.
#
# extra_bins <binaries | shell scripts>
# - This directive allows you to specify additional binaries or
# shell scripts to be included in the kdump initrd.
# Generally they are useful in conjunction with a kdump_post
# or kdump_pre binary or script which depends on these
extra_bins.
#
# extra_modules <module(s)>
# - This directive allows you to specify extra kernel modules
# that you want to be loaded in the kdump initrd.
# Multiple modules can be listed, separated by spaces, and
any
# dependent modules will automatically be included.
#
# failure_action <reboot | halt | poweroff | shell | dump_to_rootfs>
# - Action to perform in case dumping fails.
# reboot: Reboot the system.
# halt: Halt the system.
# poweroff: Power down the system.
# shell: Drop to a bash shell.
# Exiting the shell reboots the system by default,
# or perform "final_action".
# dump_to_rootfs: Dump vmcore to rootfs from initramfs
context and
# reboot by default or perform "final_action".
# Useful when non-root dump target is specified.
# The default option is "reboot".
#
# default <reboot | halt | poweroff | shell | dump_to_rootfs>
# - Same as the "failure_action" directive above, but this
directive
# is obsolete and will be removed in the future.
#
# final_action <reboot | halt | poweroff>
# - Action to perform in case dumping succeeds. Also performed
# when "shell" or "dump_to_rootfs" failure action finishes.
# Each action is same as the "failure_action" directive
above.
# The default is "reboot".
#
# force_rebuild <0 | 1>
# - By default, kdump initrd will only be rebuilt when
necessary.
# Specify 1 to force rebuilding kdump initrd every time
when kdump
# service starts.
#
# force_no_rebuild <0 | 1>
# - By default, kdump initrd will be rebuilt when necessary.
# Specify 1 to bypass rebuilding of kdump initrd.
#
# force_no_rebuild and force_rebuild options are mutually
# exclusive and they should not be set to 1 simultaneously.
#
# override_resettable <0 | 1>
# - Usually an unresettable block device can't be a dump
target.
# Specifying 1 when you want to dump even though the block
# target is unresettable
# By default, it is 0, which will not try dumping destined
to fail.
#
# dracut_args <arg(s)>
# - Pass extra dracut options when rebuilding kdump initrd.
#
# fence_kdump_args <arg(s)>
# - Command line arguments for fence_kdump_send (it can contain
# all valid arguments except hosts to send notification to).
#
# fence_kdump_nodes <node(s)>
# - List of cluster node(s) except localhost, separated by
spaces,
# to send fence_kdump notifications to.
# (this option is mandatory to enable fence_kdump).
#
#raw /dev/vg/lv_kdump
#ext4 /dev/vg/lv_kdump
#ext4 LABEL=/boot
#ext4 UUID=03138356-5e61-4ab3-b58e-27507ac41937
#virtiofs myfs
#nfs my.server.com:/export/tmp
#nfs [2001:db8::1:2:3:4]:/export/tmp
#ssh [email protected]
#ssh user@2001:db8::1:2:3:4
#sshkey /root/.ssh/kdump_id_rsa
auto_reset_crashkernel yes
path /var/crash
core_collector makedumpfile -l --message-level 7 -d 31
#core_collector scp
#kdump_post /var/crash/scripts/kdump-post.sh
#kdump_pre /var/crash/scripts/kdump-pre.sh
#extra_bins /usr/bin/lftp
#extra_modules gfs2
#failure_action shell
#force_rebuild 1
#force_no_rebuild 1
#dracut_args --omit-drivers "cfg80211 snd" --add-drivers "ext2 ext3"
#fence_kdump_args -p 7410 -f auto -c 0 -i 10
#fence_kdump_nodes node1 node2
Regards,
Venkat.
