On 4/25/2018 8:53 AM, Lianbo Jiang wrote:
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 <lijiang(a)redhat.com>
---
Some changes based the patch v3:
1.dracut-early-kdump-module-setup.sh
-Introduce some variables to parse parameters for kernel commandline and
initrd.
-It will use "dracut --add earlykdump --force" to rebuild the new
It's very nice not to affect initramfs by default!
initramfs for the early kdump.
2.early-kdump-howto.txt
-update the usage about the early kdump.
dracut-early-kdump-module-setup.sh | 42 ++++++++++++++++++++
dracut-early-kdump.sh | 81 ++++++++++++++++++++++++++++++++++++++
early-kdump-howto.txt | 50 +++++++++++++++++++++++
kexec-tools.spec | 11 ++++++
4 files changed, 184 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..5872305
--- /dev/null
+++ b/dracut-early-kdump-module-setup.sh
@@ -0,0 +1,42 @@
+#!/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-${kdump_kver}kdump.img"
+}
+
+install() {
+ inst_simple "/etc/sysconfig/kdump" "/etc/sysconfig/kdump"
+ inst_simple "/usr/sbin/kexec" "/usr/sbin/kexec"
+ inst_script "/lib/kdump/kdump-lib.sh" "/lib/kdump-lib.sh"
+ inst_hook cmdline 00 "$moddir/early-kdump.sh"
+ prepare_kernel_initrd
+ inst_simple "$KDUMP_KERNEL"
+ inst_simple "$KDUMP_INITRD"
+}
diff --git a/dracut-early-kdump.sh b/dracut-early-kdump.sh
new file mode 100755
index 0000000..2a746b4
--- /dev/null
+++ b/dracut-early-kdump.sh
@@ -0,0 +1,81 @@
+#! /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 "$EARLY_KDUMP_KERNELVER" ]; then
+ EARLY_KDUMP_KERNELVER=`uname -r`
+ fi
+
EARLY_KDUMP_KERNEL="${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"
With a KDUMP_KERNELVER setting, it fails to load the early-kdump kernel.
[root@fedora ~]# grep KDUMP_KERNELVER /etc/sysconfig/kdump
KDUMP_KERNELVER="4.16.0-0.rc6.git1.1.fc29.x86_64"
Apr 27 17:03:45 fedora dracut-cmdline[199]: Cannot open
`/boot/vmlinuz-4.17.0-0.rc1.git3.1.fc29.x86_64': No such file or directory
Apr 27 17:03:45 fedora dracut-cmdline[199]: kexec: failed to load early-kdump kernel
It looks like the KDUMP_KERNELVER in /etc/sysconfig/kdump is not used
here and the EARLY_KDUMP_KERNELVER is always set to `uname -r`.
Thanks,
Kazu
> +}
> +
> +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..07da8eb
> --- /dev/null
> +++ b/early-kdump-howto.txt
> @@ -0,0 +1,50 @@
> +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.
> +
> +For early kdump, if you need to rebuild the initramfs, please manually execute
> +dracut command:
> + # dracut --add earlykdump --force> +
> +By the way, 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.
> +
> +Next up, we need to add "rd.earlykdump" to enable early kdump in grub.
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 f04527c..303b971 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
> @@ -136,6 +139,7 @@ rm -f kexec-tools.spec.in
> cp %{SOURCE10} .
> cp %{SOURCE21} .
> cp %{SOURCE27} .
> +cp %{SOURCE28} .
>
> make
> %ifarch %{ix86} x86_64 ppc64 s390x ppc64le aarch64
> @@ -194,6 +198,7 @@ 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
> @@ -207,6 +212,11 @@ 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
> @@ -305,6 +315,7 @@ 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
>