kexec-tools: bump version and add support for crashdump kernel
split kexec-tools into two packages, kexec and kdump. * kexec to simply execute a new kernel * kdump is for loading and collecting debris of a crashed kernel with support for kdump forensics. In order to properly support booting into a crashkernel, an init script as well as UCI configuration has been added. As modifying the kernel cmdline is required for this to work in x86 platforms use an uci-defaults script to modify /boot/grub/grub.cfg. To test collecting crash information, use the 'c' sysrq-trigger, ie. echo c > /proc/sysrq-trigger This should result in the crash kernel being executed and (depending on the configution) dmesg and/or vmcore getting saved. To check if the crash kernel was loaded properly, use the 'status' command of the kdump init script. Signed-off-by: Daniel Golle <daniel@makrotopia.org>v19.07.3_mercusys_ac12_duma
Daniel Golle
7 years ago
parent
8b486ec2b5
commit
5e4bb476c0
@ -0,0 +1,7 @@
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config kdump
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option enabled '1'
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option save_dmesg '1'
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option save_vmcore '0'
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# using an external partition to store vmcore is highly recommended!
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# option path '/mnt/crashdump'
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@ -0,0 +1,11 @@
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#!/bin/sh
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case $(uname -m) in
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i?86|x86_64)
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if ! grep -q crashkernel /boot/grub/grub.cfg; then
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mount /boot -o remount,rw
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sed -i 's/linux.*/& crashkernel=32M@32M/' /boot/grub/grub.cfg
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mount /boot -o remount,ro
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fi
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;;
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esac
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@ -0,0 +1,182 @@
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#!/bin/sh /etc/rc.common
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START=41
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STOP=98
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EXTRA_COMMANDS="status"
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EXTRA_HELP=" status Print crashkernel status"
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verify_kdump() {
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local cfg="$1"
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local enabled
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local path
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local save_vmcore
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local save_dmesg
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config_get_bool enabled "$cfg" enabled 1
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config_get_bool save_dmesg "$cfg" save_dmesg 1
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config_get_bool save_vmcore "$cfg" save_vmcore 0
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[ "$enabled" -gt 0 ] || return 2
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[ "$save_dmesg" -gt 0 ] || [ "$save_vmcore" -gt 0 ] || return 2
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config_get path "$cfg" path "/"
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[ -d "$path" ] || mkdir -p "$path" 2>/dev/null || return 1
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}
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run_kdump() {
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local cfg="$1"
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local enabled
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local path
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local save_vmcore
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local save_dmesg
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config_get_bool enabled "$cfg" enabled 1
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[ "$enabled" -gt 0 ] || return
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config_get_bool save_dmesg "$cfg" save_dmesg 1
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config_get_bool save_vmcore "$cfg" save_vmcore 0
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config_get path "$cfg" path "/"
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timestamp=$(date "+%Y%m%dT%H%M%S")
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if [ "$save_vmcore" -eq 1 ]; then
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# would like 'sparse' but busybox doesn't support it
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dd if=/proc/vmcore of="$path/vmcore-$timestamp" conv=fsync bs=1M
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fi
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if [ "$save_dmesg" -eq 1 ]; then
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vmcore-dmesg /proc/vmcore > "$path/dmesg-$timestamp"
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fi
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sync
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reboot -f
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}
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find_kernel() {
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. /lib/functions.sh
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local kernel
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kernel="$BOOT_IMAGE"
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if [ -r "$kernel" ]; then
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echo $kernel
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return 0
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fi
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kernel="$(find_mtd_part kernel)"
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if [ -r "$kernel" ]; then
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echo $kernel
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return 0
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fi
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for voldir in /sys/class/ubi/ubi*_*; do
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[ ! -e "$voldir" ] && continue
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if [ "$(cat "${voldir}/name")" = "kernel" ]; then
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kernel="/dev/$(basename "$voldir")"
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echo $kernel
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return 0
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fi
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done
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return 1
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}
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load_crashkernel() {
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local append_cmdline
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local kernel
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kernel="$(find_kernel)"
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[ $? -gt 0 ] && return 1
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case "$(uname -m)" in
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i?86|x86_64)
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grep -q "crashkernel=" /proc/cmdline || return 1
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append_cmdline="1 irqpoll reset_devices maxcpus=1"
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;;
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arm*)
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append_cmdline="1 maxcpus=1 reset_devices"
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;;
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esac
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kexec -p "$kernel" --reuse-cmdline --append="$append_cmdline"
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return $?
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}
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start() {
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local retval
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if [ ! -e /sys/kernel/kexec_crash_loaded ]; then
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return 1
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fi
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if [ -e /proc/vmcore ]; then
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config_load kdump
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config_foreach run_kdump kdump
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else
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config_load kdump
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config_foreach verify_kdump kdump
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retval=$?
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[ $retval = 1 ] && return 1
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[ $retval = 0 ] && load_crashkernel
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return $?
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fi
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}
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stop() {
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[ "$(cat /sys/kernel/kexec_crash_loaded)" = "1" ] || return
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if [ -e "$BOOT_IMAGE" ]; then
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kexec -p -u "$BOOT_IMAGE"
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fi
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}
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status() {
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local retval kernel
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if [ ! -e /sys/kernel/kexec_crash_loaded ]; then
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echo "crashdump not supported by kernel"
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return
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fi
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if [ $(cat /sys/kernel/kexec_crash_size) -eq 0 ]; then
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echo "memory for crashdump kernel not reserved!"
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echo "check crashkernel= kernel cmdline parameter"
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echo "(a reboot is required after installing kdump)"
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return
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fi
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kernel="$(find_kernel)"
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if [ $? -gt 0 ]; then
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echo "cannot find kernel image"
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return
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else
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echo "using kernel image $kernel"
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fi
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echo -n "kdump configuration is "
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config_load kdump
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retval=$?
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if [ $retval = 0 ]; then
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if [ "$(config_foreach echo kdump)" ]; then
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config_foreach verify_kdump kdump
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retval=$?
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else
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retval=1
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fi
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fi
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if [ $retval = 0 ]; then
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echo "valid"
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elif [ $retval = 2 ]; then
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echo "disabled"
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else
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echo "BROKEN"
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fi
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echo -n "kexec crash kernel "
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if [ "$(cat /sys/kernel/kexec_crash_loaded)" = "0" ]; then
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echo -n "not "
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fi
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echo "loaded"
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}
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