From 17040648851ec76357e11d65c961d7ae7effd7f7 Mon Sep 17 00:00:00 2001 From: Lianbo Jiang Date: Tue, 22 May 2018 18:15:08 +0800 Subject: [PATCH] Add early kdump support in initramfs. Kdump service starts too late, so early crashes will have no chance to get kdump kernel booting, this will cause crash information to be lost. It is necessary to add a dracut module in order to load crash kernel and initramfs as early as possible. You can provide "rd.early kdump" in grub commandline to enable, then the early kdump will load those files like the normal kdump, which is disabled by default. For the normal kdump service, it can check whether the early kdump has loaded the crash kernel and initramfs. It has no conflict with the early kdump. If you rebuild the new initramfs for early kdump, the new initramfs size will become large, because it will put the vmlinuz and kdump initramfs into the new initramfs. In addition, early kdump doesn't support fadump. Signed-off-by: Lianbo Jiang Reviewed-by: Kazuhito Hagio Acked-by: Dave Young --- dracut-early-kdump-module-setup.sh | 44 ++++++++++++++++ dracut-early-kdump.sh | 84 ++++++++++++++++++++++++++++++ early-kdump-howto.txt | 54 +++++++++++++++++++ kexec-tools.spec | 11 ++++ 4 files changed, 193 insertions(+) create mode 100755 dracut-early-kdump-module-setup.sh create mode 100755 dracut-early-kdump.sh create mode 100644 early-kdump-howto.txt diff --git a/dracut-early-kdump-module-setup.sh b/dracut-early-kdump-module-setup.sh new file mode 100755 index 0000000..7613fbc --- /dev/null +++ b/dracut-early-kdump-module-setup.sh @@ -0,0 +1,44 @@ +#!/bin/bash + +. /etc/sysconfig/kdump +. /lib/kdump/kdump-lib.sh + +KDUMP_KERNEL="" +KDUMP_INITRD="" + +check() { + if [ ! -f /etc/sysconfig/kdump ] || [ ! -f /lib/kdump/kdump-lib.sh ]\ + || [ -n "${IN_KDUMP}" ] + then + return 1 + fi + return 255 +} + +depends() { + echo "base shutdown" + return 0 +} + +prepare_kernel_initrd() { + KDUMP_BOOTDIR=$(check_boot_dir "${KDUMP_BOOTDIR}") + if [ -z "$KDUMP_KERNELVER" ]; then + kdump_kver=`uname -r` + else + kdump_kver=$KDUMP_KERNELVER + fi + KDUMP_KERNEL="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${kdump_kver}${KDUMP_IMG_EXT}" + KDUMP_INITRD="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img" +} + +install() { + inst_multiple tail find cut dirname hexdump + inst_simple "/etc/sysconfig/kdump" + inst_binary "/usr/sbin/kexec" + inst_binary "/usr/bin/gawk" "/usr/bin/awk" + inst_script "/lib/kdump/kdump-lib.sh" "/lib/kdump-lib.sh" + inst_hook cmdline 00 "$moddir/early-kdump.sh" + prepare_kernel_initrd + inst_binary "$KDUMP_KERNEL" + inst_binary "$KDUMP_INITRD" +} diff --git a/dracut-early-kdump.sh b/dracut-early-kdump.sh new file mode 100755 index 0000000..34a9909 --- /dev/null +++ b/dracut-early-kdump.sh @@ -0,0 +1,84 @@ +#! /bin/sh + +KEXEC=/sbin/kexec +standard_kexec_args="-p" + +EARLY_KDUMP_INITRD="" +EARLY_KDUMP_KERNEL="" +EARLY_KDUMP_CMDLINE="" +EARLY_KDUMP_KERNELVER="" +EARLY_KEXEC_ARGS="" + +. /etc/sysconfig/kdump +. /lib/dracut-lib.sh +. /lib/kdump-lib.sh + +prepare_parameters() +{ + EARLY_KDUMP_CMDLINE=$(prepare_cmdline "${KDUMP_COMMANDLINE}" "${KDUMP_COMMANDLINE_REMOVE}" "${KDUMP_COMMANDLINE_APPEND}") + KDUMP_BOOTDIR=$(check_boot_dir "${KDUMP_BOOTDIR}") + + #make early-kdump kernel string + if [ -z "$KDUMP_KERNELVER" ]; then + EARLY_KDUMP_KERNELVER=`uname -r` + else + EARLY_KDUMP_KERNELVER=$KDUMP_KERNELVER + fi + + EARLY_KDUMP_KERNEL="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${EARLY_KDUMP_KERNELVER}${KDUMP_IMG_EXT}" + + #make early-kdump initrd string + EARLY_KDUMP_INITRD="${KDUMP_BOOTDIR}/initramfs-${EARLY_KDUMP_KERNELVER}kdump.img" +} + +early_kdump_load() +{ + check_kdump_feasibility + if [ $? -ne 0 ]; then + return 1 + fi + + if is_fadump_capable; then + echo "WARNING: early kdump doesn't support fadump." + return 1 + fi + + check_current_kdump_status + if [ $? == 0 ]; then + return 1 + fi + + prepare_parameters + + EARLY_KEXEC_ARGS=$(prepare_kexec_args "${KEXEC_ARGS}") + + if is_secure_boot_enforced; then + echo "Secure Boot is enabled. Using kexec file based syscall." + EARLY_KEXEC_ARGS="$EARLY_KEXEC_ARGS -s" + fi + + $KEXEC ${EARLY_KEXEC_ARGS} $standard_kexec_args \ + --command-line="$EARLY_KDUMP_CMDLINE" \ + --initrd=$EARLY_KDUMP_INITRD $EARLY_KDUMP_KERNEL + if [ $? == 0 ]; then + echo "kexec: loaded early-kdump kernel" + return 0 + else + echo "kexec: failed to load early-kdump kernel" + return 1 + fi +} + +set_early_kdump() +{ + if getargbool 0 rd.earlykdump; then + echo "early-kdump is enabled." + early_kdump_load + else + echo "early-kdump is disabled." + fi + + return 0 +} + +set_early_kdump diff --git a/early-kdump-howto.txt b/early-kdump-howto.txt new file mode 100644 index 0000000..fe4f13f --- /dev/null +++ b/early-kdump-howto.txt @@ -0,0 +1,54 @@ +Early Kdump HOWTO + +Introduction + +Kdump service starts too late, so early crashes will have no chance to get +kdump kernel booting, this will cause crash information to be lost. It is +necessary to add a dracut module in order to load crash kernel and initramfs +as early as possible. You can provide "rd.earlykdump" in grub commandline +to enable, then the early kdump will load those files like the normal kdump, +which is disabled by default. + +For the normal kdump service, it can check whether the early kdump has loaded +the crash kernel and initramfs. It has no conflict with the early kdump. + +How to configure early kdump: + +We assume if you're reading this document, you should already have kexec-tools +installed. + +You can rebuild the initramfs with earlykdump support with below steps: +1. start kdump service to make sure kdump initramfs is created. + # systemctl start kdump + +2. rebuild system initramfs with earlykdump support. + # dracut --add earlykdump + +3. add rd.earlykdump in grub kernel command line. + +Note: earlykdump initramfs size will be large because it includes vmlinuz and +kdump initramfs. And for step 2 if you are sure to overwrite system initramfs +you can backup the original initramfs and use "--force" option. + +After making said changes, reboot your system to take effect. Of course, if you +want to disable early kdump, you can simply remove "rd.earlykdump" from kernel +boot parameters in grub, and reboot system like above. + +Once the boot is completed, you can check the status of the early kdump support +on the command prompt: + + # journalctl -x|grep early-kdump + +Then, you will see some useful logs, for exapmle: + +1. if early kdump is successful. +Mar 09 09:57:56 localhost.localdomain dracut-cmdline[190]: early-kdump is enabled. +Mar 09 09:57:56 localhost.localdomain dracut-cmdline[190]: kexec: loaded early- +kdump kernel + +2. if early kdump is disabled. +Mar 09 10:02:47 localhost.localdomain dracut-cmdline[189]: early-kdump is disabled. + +Limitation + +At present, early kdump doesn't support fadump. diff --git a/kexec-tools.spec b/kexec-tools.spec index 2739039..60fafbc 100644 --- a/kexec-tools.spec +++ b/kexec-tools.spec @@ -29,6 +29,7 @@ Source24: kdump-lib-initramfs.sh Source25: kdump.sysconfig.ppc64le Source26: kdumpctl.8 Source27: live-image-kdump-howto.txt +Source28: early-kdump-howto.txt ####################################### # These are sources for mkdumpramfs @@ -42,6 +43,8 @@ Source104: dracut-kdump-emergency.service Source105: dracut-kdump-error-handler.service Source106: dracut-kdump-capture.service Source107: dracut-kdump-emergency.target +Source108: dracut-early-kdump.sh +Source109: dracut-early-kdump-module-setup.sh Requires(post): systemd-units Requires(preun): systemd-units @@ -132,6 +135,7 @@ rm -f kexec-tools.spec.in cp %{SOURCE10} . cp %{SOURCE21} . cp %{SOURCE27} . +cp %{SOURCE28} . make %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64 @@ -190,6 +194,7 @@ make -C kdump-anaconda-addon install DESTDIR=$RPM_BUILD_ROOT %find_lang kdump-anaconda-addon %define remove_dracut_prefix() %(echo -n %1|sed 's/.*dracut-//g') +%define remove_dracut_early_kdump_prefix() %(echo -n %1|sed 's/.*dracut-early-kdump-//g') # deal with dracut modules mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase @@ -203,6 +208,11 @@ cp %{SOURCE106} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpb cp %{SOURCE107} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE107}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE100}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE101}} +mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump +cp %{SOURCE108} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_prefix %{SOURCE108}} +cp %{SOURCE109} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_early_kdump_prefix %{SOURCE109}} +chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_prefix %{SOURCE108}} +chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlykdump/%{remove_dracut_early_kdump_prefix %{SOURCE109}} %define dracutlibdir %{_prefix}/lib/dracut @@ -301,6 +311,7 @@ done %license COPYING %doc TODO %doc kexec-kdump-howto.txt +%doc early-kdump-howto.txt %doc kdump-in-cluster-environment.txt %doc live-image-kdump-howto.txt %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64