From 5bb5be045ca7890f397a84f1ee82c1e331e63307 Mon Sep 17 00:00:00 2001 From: Hari Bathini Date: Fri, 25 Jul 2014 00:09:07 +0530 Subject: [PATCH] kdump: Rebuild default initrd for firmware assisted dump The current kdump infrastructure builds a separate initrd which then gets loaded into memory by kexec-tools for use by kdump kernel. But firmware assisted dump (FADUMP) does not use kexec-based approach. After crash, firmware reboots the partition and loads grub loader like the normal booting process does. Hence in the FADUMP approach, the second kernel (after crash) will always use the default initrd (OS built). So, to support FADUMP, change is required, as in to add dump capturing steps, in this initrd. The current kdumpctl script implementation already has the code to build initrd using mkdumprd. This patch uses the new '--rebuild' option introduced, in dracut, to incrementally build the initramfs image. Before rebuilding, we may need to probe the initrd image for fadump support, to avoid rebuilding the initrd image multiple times unnecessarily. This can be done using "lsinitrd" tool with the newly proposed '--mod' option & inspecting the presence of "kdumpbase" in the list of modules of default initrd image. We rebuild the image if only "kdumpbase" module is missing in the initrd image. Also, before rebuilding, a backup of default initrd image is taken. Kexec-tools package in rhel7 is now enhanced to insert a out-of-tree kdump module for dracut, which is responsible for adding vmcore capture steps into initrd, if dracut is invoked with "IN_KDUMP" environment variable set to 1. mkdumprd script exports "IN_KDUMP=1" environment variable before invoking dracut to build kdump initrd. This patch relies on this current mechanism of kdump init script. Signed-off-by: Mahesh Salgaonkar Signed-off-by: Hari Bathini Acked-by: Vivek Goyal --- kdumpctl | 85 ++++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 77 insertions(+), 8 deletions(-) diff --git a/kdumpctl b/kdumpctl index 0cfe2b9..ff09b9a 100755 --- a/kdumpctl +++ b/kdumpctl @@ -9,6 +9,7 @@ MKDUMPRD="/sbin/mkdumprd -f" SAVE_PATH=/var/crash SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa" DUMP_TARGET="" +TARGET_INITRD="" FADUMP_ENABLED_SYS_NODE="/sys/kernel/fadump_enabled" FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered" #kdump shall be the default dump mode @@ -143,13 +144,47 @@ save_core() fi } -rebuild_initrd() +rebuild_fadump_initrd() { - $MKDUMPRD $kdump_initrd $kdump_kver + local target_initrd_tmp + + # backup fadump initrd for reference before replacing it + backup_initrd + + target_initrd_tmp="$TARGET_INITRD.tmp" + $MKDUMPRD $target_initrd_tmp --rebuild $TARGET_INITRD --kver $kdump_kver + if [ $? != 0 ]; then + echo "mkdumprd: failed to rebuild initrd with fadump support" >&2 + return 1 + fi + + # updating fadump initrd + mv $target_initrd_tmp $TARGET_INITRD + sync + + return 0 +} + +rebuild_kdump_initrd() +{ + $MKDUMPRD $TARGET_INITRD $kdump_kver if [ $? != 0 ]; then echo "mkdumprd: failed to make kdump initrd" >&2 return 1 fi + + return 0 +} + +rebuild_initrd() +{ + if [ $DEFAULT_DUMP_MODE == "fadump" ]; then + rebuild_fadump_initrd + else + rebuild_kdump_initrd + fi + + return $? } #$1: the files to be checked with IFS=' ' @@ -174,6 +209,18 @@ check_executable() done } +backup_initrd() +{ + local target_initrd_bak + + # Check if backup initrd is already present. + target_initrd_bak="$TARGET_INITRD.bak" + if [ ! -e $target_initrd_bak ];then + echo "Backing up $TARGET_INITRD" + cp $TARGET_INITRD $target_initrd_bak + fi +} + check_config() { local nr @@ -240,10 +287,24 @@ get_pcs_cluster_modified_files() echo $modified_files } +setup_target_initrd() +{ + if [ $DEFAULT_DUMP_MODE == "fadump" ]; then + TARGET_INITRD="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}.img" + if [ ! -s "$TARGET_INITRD" ]; then + echo "Error: No initrd found to rebuild!" + return 1 + fi + else + TARGET_INITRD="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img" + fi +} + check_rebuild() { local extra_modules modified_files="" local _force_rebuild force_rebuild="0" + local initramfs_has_fadump if [ -z "$KDUMP_KERNELVER" ]; then kdump_kver=`uname -r` @@ -252,7 +313,10 @@ check_rebuild() fi kdump_kernel="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${kdump_kver}${KDUMP_IMG_EXT}" - kdump_initrd="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img" + setup_target_initrd + if [ $? -ne 0 ]; then + return 1 + fi _force_rebuild=`grep ^force_rebuild $KDUMP_CONFIG_FILE 2>/dev/null` if [ $? -eq 0 ]; then @@ -269,8 +333,8 @@ check_rebuild() #check to see if dependent files has been modified #since last build of the image file - if [ -f $kdump_initrd ]; then - image_time=`stat -c "%Y" $kdump_initrd 2>/dev/null` + if [ -f $TARGET_INITRD ]; then + image_time=`stat -c "%Y" $TARGET_INITRD 2>/dev/null` else image_time=0 fi @@ -295,10 +359,15 @@ check_rebuild() fi done + #check if target initrd has fadump support + initramfs_has_fadump=`lsinitrd -m $TARGET_INITRD | grep ^kdumpbase$ | wc -l` + if [ $image_time -eq 0 ]; then echo -n "No kdump initial ramdisk found."; echo + elif [ $DEFAULT_DUMP_MODE == "fadump" ] && [ "$initramfs_has_fadump" -eq "0" ]; then + echo "$TARGET_INITRD has no fadump support" elif [ "$force_rebuild" != "0" ]; then - echo -n "Force rebuild $kdump_initrd"; echo + echo -n "Force rebuild $TARGET_INITRD"; echo elif [ -n "$modified_files" ]; then echo "Detected change(s) in the following file(s):" echo -n " "; echo "$modified_files" | sed 's/\s/\n /g' @@ -306,7 +375,7 @@ check_rebuild() return 0 fi - echo "Rebuilding $kdump_initrd" + echo "Rebuilding $TARGET_INITRD" rebuild_initrd return $? } @@ -359,7 +428,7 @@ load_kdump() $KEXEC $KEXEC_ARGS $standard_kexec_args \ --command-line="$KDUMP_COMMANDLINE" \ - --initrd=$kdump_initrd $kdump_kernel 2>/dev/null + --initrd=$TARGET_INITRD $kdump_kernel 2>/dev/null if [ $? == 0 ]; then echo "kexec: loaded kdump kernel" return 0