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fadump: isolate fadump initramfs image within the default one

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In case of fadump, the initramfs image has to be built to boot into
the production environment as well as to offload the active crash dump
to the specified dump target (for boot after crash). As the same image
would be used for both boot scenarios, it could not be built optimally
while accommodating both cases.

Use --include to include the initramfs image built for offloading
active crash dump to the specified dump target. Also, introduce a new
out-of-tree dracut module (99zz-fadumpinit) that installs a customized
init program while moving the default /init to /init.dracut. This
customized init program is leveraged to isolate fadump image within
the default initramfs image by kicking off default boot process
(exec /init.dracut) for regular boot scenario and activating fadump
initramfs image, if the system is booting after a crash.

If squash is available, ensure default initramfs image is also built
with squash module to reduce memory consumption in capture kernel.

Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Signed-off-by: Kairui Song <kasong@redhat.com>
Acked-by: Kairui Song <kasong@redhat.com>
This commit is contained in:
Hari Bathini 2021-06-23 20:06:48 +05:30 committed by Kairui Song
parent c4749f9c57
commit fa9201b240
8 changed files with 162 additions and 32 deletions
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44
dracut-fadump-init-fadump.sh Executable file
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@ -0,0 +1,44 @@
#!/bin/sh
export PATH=/usr/bin:/usr/sbin
export SYSTEMD_IN_INITRD=lenient
[ -e /proc/mounts ] ||
(mkdir -p /proc && mount -t proc -o nosuid,noexec,nodev proc /proc)
grep -q '^sysfs /sys sysfs' /proc/mounts ||
(mkdir -p /sys && mount -t sysfs -o nosuid,noexec,nodev sysfs /sys)
grep -q '^none / ' /proc/mounts || grep -q '^rootfs / ' /proc/mounts && ROOTFS_IS_RAMFS=1
if [ -f /proc/device-tree/rtas/ibm,kernel-dump ] || [ -f /proc/device-tree/ibm,opal/dump/mpipl-boot ]; then
mkdir /newroot
mount -t ramfs ramfs /newroot
if [ $ROOTFS_IS_RAMFS ]; then
for FILE in $(ls -A /fadumproot/); do
mv /fadumproot/$FILE /newroot/
done
exec switch_root /newroot /init
else
mkdir /newroot/sys /newroot/proc /newroot/oldroot
mount --move /proc /newroot/proc
mount --move /sys /newroot/sys
cp --reflink=auto --sparse=auto --preserve=mode,timestamps,links -dfr /fadumproot/. /newroot/
cd /newroot && pivot_root . oldroot
loop=1
while [ $loop ]; do
unset loop
while read -r _ mp _; do
case $mp in
/oldroot/*) umount "$mp" && loop=1 ;;
esac
done </proc/mounts
done
umount -l oldroot
exec /init
fi
else
exec /init.dracut
fi

23
dracut-fadump-module-setup.sh Normal file
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@ -0,0 +1,23 @@
#!/bin/bash
check() {
return 255
}
depends() {
return 0
}
install() {
mv -f "$initdir/init" "$initdir/init.dracut"
inst_script "$moddir/init-fadump.sh" /init
chmod a+x "$initdir/init"
# Install required binaries for the init script (init-fadump.sh)
inst_multiple sh modprobe grep mkdir mount
if dracut_module_included "squash"; then
inst_multiple cp pivot_root umount
else
inst_multiple ls mv switch_root
fi
}

16
dracut-module-setup.sh
View File

@ -27,17 +27,7 @@ depends() {
[[ " $omit_dracutmodules " != *\ $1\ * ]] && _dep="$_dep $1"
}
is_squash_available() {
for kmodule in squashfs overlay loop; do
if [ -z "$KDUMP_KERNELVER" ]; then
modprobe --dry-run $kmodule &>/dev/null || return 1
else
modprobe -S $KDUMP_KERNELVER --dry-run $kmodule &>/dev/null || return 1
fi
done
}
if is_squash_available && ! is_fadump_capable; then
if is_squash_available; then
add_opt_module squash
else
dwarning "Required modules to build a squashed kdump image is missing!"
@ -1087,7 +1077,5 @@ install() {
${initdir}/etc/lvm/lvm.conf &>/dev/null
# Save more memory by dropping switch root capability
if ! is_fadump_capable; then
dracut_no_switch_root
fi
dracut_no_switch_root
}

10
kdump-lib.sh
View File

@ -19,6 +19,16 @@ is_fadump_capable()
return 1
}
is_squash_available() {
for kmodule in squashfs overlay loop; do
if [ -z "$KDUMP_KERNELVER" ]; then
modprobe --dry-run $kmodule &>/dev/null || return 1
else
modprobe -S $KDUMP_KERNELVER --dry-run $kmodule &>/dev/null || return 1
fi
done
}
perror_exit() {
derror "$@"
exit 1

22
kdumpctl
View File

@ -8,6 +8,7 @@ KEXEC_ARGS=""
KDUMP_CONFIG_FILE="/etc/kdump.conf"
KDUMP_LOG_PATH="/var/log"
MKDUMPRD="/sbin/mkdumprd -f"
MKFADUMPRD="/sbin/mkfadumprd"
DRACUT_MODULES_FILE="/usr/lib/dracut/modules.txt"
SAVE_PATH=/var/crash
SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
@ -104,25 +105,10 @@ save_core()
rebuild_fadump_initrd()
{
local target_initrd_tmp
# this file tells the initrd is fadump enabled
touch /tmp/fadump.initramfs
target_initrd_tmp="$TARGET_INITRD.tmp"
ddebug "rebuild fadump initrd: $target_initrd_tmp $DEFAULT_INITRD_BAK $KDUMP_KERNELVER"
$MKDUMPRD $target_initrd_tmp --rebuild $DEFAULT_INITRD_BAK --kver $KDUMP_KERNELVER \
-i /tmp/fadump.initramfs /etc/fadump.initramfs
if [ $? != 0 ]; then
derror "mkdumprd: failed to rebuild initrd with fadump support"
rm -f /tmp/fadump.initramfs
if ! $MKFADUMPRD "$DEFAULT_INITRD_BAK" "$TARGET_INITRD" --kver "$KDUMP_KERNELVER"; then
derror "mkfadumprd: failed to make fadump initrd"
return 1
fi
rm -f /tmp/fadump.initramfs
# updating fadump initrd
ddebug "updating fadump initrd: $target_initrd_tmp $TARGET_INITRD"
mv $target_initrd_tmp $TARGET_INITRD
sync
return 0
}
@ -612,7 +598,7 @@ check_rebuild()
#in case of fadump mode, check whether the default/target
#initrd is already built with dump capture capability
if [ "$DEFAULT_DUMP_MODE" == "fadump" ]; then
capture_capable_initrd=$(lsinitrd -f $DRACUT_MODULES_FILE $TARGET_INITRD | grep ^kdumpbase$ | wc -l)
capture_capable_initrd=$(lsinitrd -f $DRACUT_MODULES_FILE $TARGET_INITRD | grep -e ^kdumpbase$ -e ^zz-fadumpinit$ | wc -l)
fi
fi

14
kexec-tools.spec
View File

@ -39,6 +39,7 @@ Source28: kdump-udev-throttler
Source29: kdump.sysconfig.aarch64
Source30: 60-kdump.install
Source31: kdump-logger.sh
Source32: mkfadumprd
#######################################
# These are sources for mkdumpramfs
@ -54,6 +55,9 @@ Source107: dracut-kdump-emergency.target
Source108: dracut-early-kdump.sh
Source109: dracut-early-kdump-module-setup.sh
Source200: dracut-fadump-init-fadump.sh
Source201: dracut-fadump-module-setup.sh
Requires(post): systemd-units
Requires(preun): systemd-units
Requires(postun): systemd-units
@ -183,6 +187,7 @@ SYSCONFIG=$RPM_SOURCE_DIR/kdump.sysconfig.%{_target_cpu}
install -m 644 $SYSCONFIG $RPM_BUILD_ROOT%{_sysconfdir}/sysconfig/kdump
install -m 755 %{SOURCE7} $RPM_BUILD_ROOT/usr/sbin/mkdumprd
install -m 755 %{SOURCE32} $RPM_BUILD_ROOT/usr/sbin/mkfadumprd
install -m 644 %{SOURCE8} $RPM_BUILD_ROOT%{_sysconfdir}/kdump.conf
install -m 644 kexec/kexec.8 $RPM_BUILD_ROOT%{_mandir}/man8/kexec.8
install -m 644 %{SOURCE12} $RPM_BUILD_ROOT%{_mandir}/man8/mkdumprd.8
@ -218,6 +223,7 @@ install -m 644 makedumpfile-%{mkdf_ver}/eppic_scripts/* $RPM_BUILD_ROOT/usr/shar
%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')
%define remove_dracut_fadump_prefix() %(echo -n %1|sed 's/.*dracut-fadump-//g')
# deal with dracut modules
mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase
@ -235,6 +241,13 @@ cp %{SOURCE108} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99earlyk
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}}
%ifarch ppc64 ppc64le
mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99zz-fadumpinit
cp %{SOURCE200} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99zz-fadumpinit/%{remove_dracut_fadump_prefix %{SOURCE200}}
cp %{SOURCE201} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99zz-fadumpinit/%{remove_dracut_fadump_prefix %{SOURCE201}}
chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99zz-fadumpinit/%{remove_dracut_fadump_prefix %{SOURCE200}}
chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99zz-fadumpinit/%{remove_dracut_fadump_prefix %{SOURCE201}}
%endif
%define dracutlibdir %{_prefix}/lib/dracut
@ -316,6 +329,7 @@ done
/usr/sbin/makedumpfile
%endif
/usr/sbin/mkdumprd
/usr/sbin/mkfadumprd
/usr/sbin/vmcore-dmesg
%{_bindir}/*
%{_datadir}/kdump

5
mkdumprd
View File

@ -452,6 +452,11 @@ then
add_dracut_arg "--add-drivers" \"$extra_modules\"
fi
# TODO: The below check is not needed anymore with the introduction of
# 'zz-fadumpinit' module, that isolates fadump's capture kernel initrd,
# but still sysroot.mount unit gets generated based on 'root=' kernel
# parameter available in fadump case. So, find a way to fix that first
# before removing this check.
if ! is_fadump_capable; then
# The 2nd rootfs mount stays behind the normal dump target mount,
# so it doesn't affect the logic of check_dump_fs_modified().

60
mkfadumprd Normal file
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@ -0,0 +1,60 @@
#!/bin/bash --norc
# Generate an initramfs image that isolates dump capture capability within
# the default initramfs using zz-fadumpinit dracut module.
if [ -f /etc/sysconfig/kdump ]; then
. /etc/sysconfig/kdump
fi
[[ $dracutbasedir ]] || dracutbasedir=/usr/lib/dracut
. $dracutbasedir/dracut-functions.sh
. /lib/kdump/kdump-lib.sh
. /lib/kdump/kdump-logger.sh
#initiate the kdump logger
if ! dlog_init; then
echo "mkfadumprd: failed to initiate the kdump logger."
exit 1
fi
readonly MKFADUMPRD_TMPDIR="$(mktemp -d -t mkfadumprd.XXXXXX)"
[ -d "$MKFADUMPRD_TMPDIR" ] || perror_exit "mkfadumprd: mktemp -d -t mkfadumprd.XXXXXX failed."
trap '
ret=$?;
[[ -d $MKFADUMPRD_TMPDIR ]] && rm --one-file-system -rf -- "$MKFADUMPRD_TMPDIR";
exit $ret;
' EXIT
# clean up after ourselves no matter how we die.
trap 'exit 1;' SIGINT
MKDUMPRD="/sbin/mkdumprd -f"
# Default boot initramfs to be rebuilt
REBUILD_INITRD="$1" && shift
TARGET_INITRD="$1" && shift
FADUMP_INITRD="$MKFADUMPRD_TMPDIR/fadump.img"
### First build an initramfs with dump capture capability
# this file tells the initrd is fadump enabled
touch "$MKFADUMPRD_TMPDIR/fadump.initramfs"
ddebug "rebuild fadump initrd: $FADUMP_INITRD $DEFAULT_INITRD $KDUMP_KERNELVER"
if ! $MKDUMPRD "$FADUMP_INITRD" -i "$MKFADUMPRD_TMPDIR/fadump.initramfs" /etc/fadump.initramfs; then
perror_exit "mkfadumprd: failed to build image with dump capture support"
fi
### Unpack the initramfs having dump capture capability
mkdir -p "$MKFADUMPRD_TMPDIR/fadumproot"
if ! (pushd "$MKFADUMPRD_TMPDIR/fadumproot" > /dev/null && lsinitrd --unpack "$MKFADUMPRD_TMPDIR/fadump.img" && \
popd > /dev/null); then
derror "mkfadumprd: failed to unpack '$MKFADUMPRD_TMPDIR'"
exit 1
fi
### Pack it into the normal boot initramfs with zz-fadumpinit module
_dracut_isolate_args="--rebuild $REBUILD_INITRD --add zz-fadumpinit -i $MKFADUMPRD_TMPDIR/fadumproot /fadumproot"
if is_squash_available; then
_dracut_isolate_args="$_dracut_isolate_args --add squash"
fi
if ! dracut --force --quiet $_dracut_isolate_args $@ "$TARGET_INITRD"; then
perror_exit "mkfadumprd: failed to setup '$TARGET_INITRD' with dump capture capability"
fi