Re: [PATCH v4 10/13] try to reset kernel crashkernel when kexec-tools updates the default crashkernel value

On Tue, Dec 28, 2021 at 08:49:27AM +0800, Coiby Xu wrote:

kexec-tools could update the default crashkernel value. When auto_reset_crashkernel=yes, reset kernel to new crashkernel value in the following two cases,

• crashkernel=auto is found in the kernel cmdline
• the kernel crashkernel was previously set by kexec-tools i.e. the kernel is using old default crashkernel value

To tell if the user is using a custom value for the kernel crashkernel or not, we assume the user would never use the default crashkernel value as custom value. When kexec-tools gets updated,

1. save the default crashkernel value of the older package to /tmp/crashkernel (for POWER system, /tmp/crashkernel_fadump is saved as well).
2. If auto_reset_crashkernel=yes, iterate all installed kernels. For each kernel, compare its crashkernel value with the old default crashkernel and reset it if yes

The implementation makes use of two RPM scriptlets [2],

• %pre is run before a package is installed so we can use it to save old default crashkernel value
• %post is run after a package installed so we can use it to try to reset kernel crashkernel

There are several problems when running kdumpctl in the RPM scripts for CoreOS/Atomic/Silverblue, for example, the lock can't be acquired by kdumpctl, "rpm-ostree kargs" can't be run and etc.. So don't enable this feature for CoreOS/Atomic/Silverblue.

Note latest shellcheck (0.8.0) gives false positives about the associative array as of this commit. And Fedora's shellcheck is 0.7.2 and can't even correctly parse the shell code because of the associative array.

[1] https://github.com/koalaman/shellcheck/issues/2399 [2] https://docs.fedoraproject.org/en-US/packaging-guidelines/Scriptlets/

Signed-off-by: Coiby Xu coxu@redhat.com

kdumpctl | 35 +++++++++++++++++++++++++++++++++++ kexec-tools.spec | 15 +++++++++++++++ 2 files changed, 50 insertions(+)

diff --git a/kdumpctl b/kdumpctl index 8b7e829f..cbafaa19 100755 --- a/kdumpctl +++ b/kdumpctl @@ -1559,6 +1559,36 @@ reset_crashkernel() [[ $_reboot == yes && $_crashkernel_changed == yes ]] && reboot }

+# 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
• _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); 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_grub "$_kernel" "$_new_default_crashkernel" "$_dump_mode" "$_fadump_val"; then
  

• 			echo "For kernel=$_kernel, crashkernel=$_new_default_crashkernel now."
  

• 		fi
  

• 	fi
  

• fi
  

• done

+}

if [[ ! -f $KDUMP_CONFIG_FILE ]]; then derror "Error: No kdump config file found!" exit 1 @@ -1624,6 +1654,11 @@ main() shift reset_crashkernel "$@" ;;

• reset-crashkernel-after-update)

• if [[ $(kdump_get_conf_val auto_reset_crashkernel) != no ]]; then
  

• 	reset_crashkernel_after_update
  

• fi
  

• ;;
  

  *) dinfo $"Usage: $0 {estimate|start|stop|status|restart|reload|rebuild|reset-crashkernel|propagate|showmem}" exit 1

diff --git a/kexec-tools.spec b/kexec-tools.spec index ab7f41fd..f439cb5a 100644 --- a/kexec-tools.spec +++ b/kexec-tools.spec @@ -258,6 +258,14 @@ 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 +if ! grep -q "ostree" /proc/cmdline && [ $1 == 2 ] && grep -q get-default-crashkernel /usr/bin/kdumpctl; then

^^^ Sorry I can not understand this condition "[ $1 == 2 ]"

• 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

Does fadump=off fall in this category?

+%endif +fi

%post # Initial installation %systemd_post kdump.service @@ -290,6 +298,13 @@ then /etc/sysconfig/kdump > /etc/sysconfig/kdump.new mv /etc/sysconfig/kdump.new /etc/sysconfig/kdump fi +if ! grep -q "ostree" /proc/cmdline && [ $1 == 2 ]; then

• kdumpctl reset-crashkernel-after-update
• rm /tmp/old_default_crashkernel 2>/dev/null || :

^^^ what is the purpose?

+%ifarch ppc64 ppc64le

• rm /tmp/old_default_crashkernel_fadump 2>/dev/null || :

^^^ as above

For the other part,

LGTM.

Thanks,

Pingfan

+%endif +fi

%postun

2.31.1