Re: [PATCH 2/2 V5] Add early kdump support in initramfs.

[lijiang]

在 2018年05月04日 04:25, Kazuhito Hagio 写道:
> On 5/1/2018 4:34 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
> >
> > Some changes based the patch v3&v4:
> > 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
> > initramfs for the early kdump.
> > 2.early-kdump-howto.txt
> > -update the usage about the early kdump.
> > 3.dracut-early-kdump.sh
> > -modify prepare_parameters() function and handle the case with
> > a "KDUMP_KERNELVER" setting.
> >
> > dracut-early-kdump-module-setup.sh | 42 +++++++++++++++++++
> >  dracut-early-kdump.sh              | 84 ++++++++++++++++++++++++++++++++++++++
> >  early-kdump-howto.txt              | 50 +++++++++++++++++++++++
> >  kexec-tools.spec                   | 11 +++++
> >  4 files changed, 187 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"
> >
> > +}
>
> There are 8-space indents only here in this file.
> > +install() {
> > inst_simple "/etc/sysconfig/kdump" "/etc/sysconfig/kdump"
> > inst_simple "/usr/sbin/kexec" "/usr/sbin/kexec"
>
> I have not had any problem with this, but according to dracut and
> its modules, I think that it should be "inst" or "inst_multiple"
> instead of "inst_simple" for executables.  Am I right?

Thank you, Kazu.
That is a good idea. Dracut has a series of function(inst_xxx) to handle different files,
it is a very good way of programming. 
It will be improved in the next patch(V6).

Lianbo
> And, there are the missing commands as I mentioned in another
> reply, so we can use the following? or a series of "inst".
>
> inst_multiple kexec tail find hexdump cut dirname

It looks like that is a good solution for this issue.

Thanks.
Lianbo
> Thanks a lot!
> Kazu
> > 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 "$KDUMP_INITRD"
> >
> > +}
> > diff --git a/dracut-early-kdump.sh b/dracut-early-kdump.sh
> > new file mode 100755
> > index 0000000..34a9909
> > --- /dev/null
> > +++ b/dracut-early-kdump.sh
> > @@ -0,0 +1,84 @@
> > +#! /bin/sh
> >
> > +KEXEC=/sbin/kexec
> > +standard_kexec_args="-p"
> >
> > +EARLY_KDUMP_INITRD=""
> > +EARLY_KDUMP_KERNEL=""
> > +EARLY_KDUMP_CMDLINE=""
> > +EARLY_KDUMP_KERNELVER=""
> > +EARLY_KEXEC_ARGS=""
> >
> > +. /etc/sysconfig/kdump
> > +. /lib/dracut-lib.sh
> > +. /lib/kdump-lib.sh
> >
> > +prepare_parameters()
> > +{
> > EARLY_KDUMP_CMDLINE=$(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..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