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Simplify the management of the kernel parameter crashkernel

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Currently, kexec-tools only updates the crashkernel to a new default
value only when both two conditions are met,
 - auto_reset_crashkernel=yes in kdump.conf
 - existing kernels or current running kernel should use the old default
   value.

To address seen corner cases, the logic to tell if the second condition
is met becomes quite complex. Instead of making the logic more complex
to support aarch64-64k, this patch drops the second condition to
simplify the management of the crashkernel kernel parameter.

Another change brought by this simplification is kexec-tools will also
set up the kernel crashkernel parameter for a fresh install (previously
it's limited to osbuild).

Note
1. This patch also stop trying to update /etc/default/grub because
   a) it only affects the static file /boot/grub2/grub.cfg
   b) grubby is recommended to change the kernel command-line parameters
      for both Fedora [1] and RHEL9 [2][3]
   c) For the cases of aarch64 and POWER, different kernels could have
      different default crashkernel value.

2. Starting with Fedora 37,  posttrans rpm scriplet distinguish between
   package install and upgrade.

[1] https://fedoraproject.org/wiki/GRUB_2
[2] https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9/html/managing_monitoring_and_updating_the_kernel/configuring-kernel-command-line-parameters_managing-monitoring-and-updating-the-kernel#changing-kernel-command-line-parameters-for-all-boot-entries_configuring-kernel-command-line-parameters
[3] https://access.redhat.com/solutions/1136173

Signed-off-by: Coiby Xu <coxu@redhat.com>
Reviewed-by: Philipp Rudo <prudo@redhat.com>
This commit is contained in:
Coiby Xu 2023-04-26 04:48:25 +08:00
parent cdc0253a3c
commit 5b31b099ae
3 changed files with 25 additions and 97 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
kdump.conf.5
View File

@ -28,9 +28,8 @@ understand how this configuration file affects the behavior of kdump.
.B auto_reset_crashkernel <yes|no>
.RS
determine 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
determine whether to reset kernel crashkernel parameter to the default value
or not when kexec-tools is updated or a new kernel is installed.
.B raw <partition>
.RS

86
kdumpctl
View File

@ -1675,72 +1675,37 @@ _is_bootloader_installed()
fi
}
# update the crashkernel value in GRUB_ETC_DEFAULT if necessary
#
# called by reset_crashkernel_after_update and inherit its array variable
# _crashkernel_vals
update_crashkernel_in_grub_etc_default_after_update()
_update_crashkernel()
{
local _crashkernel _fadump_val
local _dump_mode _old_default_crashkernel _new_default_crashkernel
local _kernel _dump_mode _old_default_crashkernel _new_default_crashkernel _fadump_val _msg
if [[ $(uname -m) == s390x ]]; then
return
fi
_crashkernel=$(_read_kernel_arg_in_grub_etc_default crashkernel)
if [[ -z $_crashkernel ]]; then
return
fi
_fadump_val=$(_read_kernel_arg_in_grub_etc_default fadump)
_dump_mode=$(get_dump_mode_by_fadump_val "$_fadump_val")
_old_default_crashkernel=${_crashkernel_vals[old_${_dump_mode}]}
_new_default_crashkernel=${_crashkernel_vals[new_${_dump_mode}]}
if [[ $_crashkernel == auto ]] ||
[[ $_crashkernel == "$_old_default_crashkernel" &&
$_new_default_crashkernel != "$_old_default_crashkernel" ]]; then
_update_kernel_arg_in_grub_etc_default crashkernel "$_new_default_crashkernel"
_kernel=$1
_dump_mode=$(get_dump_mode_by_kernel "$_kernel")
_old_default_crashkernel=$(get_grub_kernel_boot_parameter "$_kernel" crashkernel)
_new_default_crashkernel=$(kdump_get_arch_recommend_crashkernel "$_dump_mode")
if [[ $_old_default_crashkernel != "$_new_default_crashkernel" ]]; then
_fadump_val=$(get_grub_kernel_boot_parameter "$_kernel" fadump)
if _update_kernel_cmdline "$_kernel" "$_new_default_crashkernel" "$_dump_mode" "$_fadump_val"; then
_msg="For kernel=$_kernel, crashkernel=$_new_default_crashkernel now. Please reboot the system for the change to take effet."
_msg+=" Note if you don't want kexec-tools to manage the crashkernel kernel parameter, please set auto_reset_crashkernel=no in /etc/kdump.conf."
dinfo "$_msg"
fi
fi
}
# shellcheck disable=SC2154 # false positive when dereferencing an array
reset_crashkernel_after_update()
{
local _kernel _crashkernel _dump_mode _fadump_val _old_default_crashkernel _new_default_crashkernel
declare -A _crashkernel_vals
local _kernel
if ! _is_bootloader_installed; then
return
fi
_crashkernel_vals[old_kdump]=$(cat /tmp/old_default_crashkernel 2> /dev/null)
_crashkernel_vals[old_fadump]=$(cat /tmp/old_default_crashkernel_fadump 2> /dev/null)
_crashkernel_vals[new_kdump]=$(get_default_crashkernel kdump)
_crashkernel_vals[new_fadump]=$(get_default_crashkernel fadump)
for _kernel in $(_get_all_kernels_from_grubby ALL); do
_crashkernel=$(get_grub_kernel_boot_parameter "$_kernel" crashkernel)
if [[ $_crashkernel == auto ]]; then
reset_crashkernel "--kernel=$_kernel"
elif [[ -n $_crashkernel ]]; then
_dump_mode=$(get_dump_mode_by_kernel "$_kernel")
_old_default_crashkernel=${_crashkernel_vals[old_${_dump_mode}]}
_new_default_crashkernel=${_crashkernel_vals[new_${_dump_mode}]}
if [[ $_crashkernel == "$_old_default_crashkernel" ]] &&
[[ $_new_default_crashkernel != "$_old_default_crashkernel" ]]; then
_fadump_val=$(get_grub_kernel_boot_parameter "$_kernel" fadump)
if _update_kernel_cmdline "$_kernel" "$_new_default_crashkernel" "$_dump_mode" "$_fadump_val"; then
echo "For kernel=$_kernel, crashkernel=$_new_default_crashkernel now."
fi
fi
fi
_update_crashkernel "$_kernel"
done
update_crashkernel_in_grub_etc_default_after_update
}
# read the value of an environ variable from given environ file path
@ -1764,8 +1729,7 @@ _is_osbuild()
reset_crashkernel_for_installed_kernel()
{
local _installed_kernel _running_kernel _crashkernel _crashkernel_running
local _dump_mode_running _fadump_val_running
local _installed_kernel
# During package install, only try to reset crashkernel for osbuild
# thus to avoid calling grubby when installing os via anaconda
@ -1784,21 +1748,7 @@ reset_crashkernel_for_installed_kernel()
return
fi
if ! _running_kernel=$(_get_current_running_kernel_path); then
ddebug "Couldn't find current running kernel"
exit
fi
_crashkernel=$(get_grub_kernel_boot_parameter "$_installed_kernel" crashkernel)
_crashkernel_running=$(get_grub_kernel_boot_parameter "$_running_kernel" crashkernel)
_dump_mode_running=$(get_dump_mode_by_kernel "$_running_kernel")
_fadump_val_running=$(get_grub_kernel_boot_parameter "$_kernel" fadump)
if [[ $_crashkernel != "$_crashkernel_running" ]]; then
if _update_kernel_cmdline "$_installed_kernel" "$_crashkernel_running" "$_dump_mode_running" "$_fadump_val_running"; then
echo "kexec-tools has reset $_installed_kernel to use the new default crashkernel value $_crashkernel_running"
fi
fi
_update_crashkernel "$_installed_kernel"
}
main()

31
kexec-tools.spec
View File

@ -260,21 +260,6 @@ chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99zz-fadumpini
mkdir -p $RPM_BUILD_ROOT/%{dracutlibdir}/modules.d/
mv $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/* $RPM_BUILD_ROOT/%{dracutlibdir}/modules.d/
%pre
# Save the old default crashkernel values to /tmp/ when upgrading the package
# so kdumpctl later can tell if it should update the kernel crashkernel
# parameter in the posttrans scriptlet. Note this feauture of auto-updating
# the kernel crashkernel parameter currently doesn't support ostree, so skip it
# for ostree.
if [ ! -f /run/ostree-booted ] && [ $1 == 2 ] && grep -q get-default-crashkernel /usr/bin/kdumpctl; then
kdumpctl get-default-crashkernel kdump > /tmp/old_default_crashkernel 2>/dev/null
%ifarch ppc64 ppc64le
kdumpctl get-default-crashkernel fadump > /tmp/old_default_crashkernel_fadump 2>/dev/null
%endif
fi
# don't block package update
:
%post
# Initial installation
%systemd_post kdump.service
@ -341,21 +326,15 @@ do
done
%posttrans
# Try to reset kernel crashkernel value to new default value based on the old
# default value or set up crasherkernel value for osbuild
# Try to reset kernel crashkernel value to new default value or set up
# crasherkernel value for new install
#
# Note
# 1. Skip ostree systems as they are not supported.
# 2. "[ $1 == 1 ]" in posttrans scriptlet means both install and upgrade. The
# former case is used to set up crashkernel for osbuild
if [ ! -f /run/ostree-booted ] && [ $1 == 1 ]; then
# 2. For Fedora 36 and RHEL9, "[ $1 == 1 ]" in posttrans scriptlet means both install and upgrade;
# For Fedora > 36, "[ $1 == 1 ]" only means install and "[ $1 == 2 ]" means upgrade
if [ ! -f /run/ostree-booted ] && [ $1 == 1 -o $1 == 2 ]; then
kdumpctl _reset-crashkernel-after-update
rm /tmp/old_default_crashkernel 2>/dev/null
%ifarch ppc64 ppc64le
rm /tmp/old_default_crashkernel_fadump 2>/dev/null
%endif
# dnf would complain about the exit code not being 0. To keep it happy,
# always return 0
:
fi