1:39 p.m.
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 <mahesh(a)linux.vnet.ibm.com>
Signed-off-by: Hari Bathini <hbathini(a)linux.vnet.ibm.com>
---
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()
+{
+ 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 $kdump_initrd $kdump_kver
+ $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