[PATCH 0/6] kdump: Modify kdump init script to support firmware-assisted dump

[Hari Bathini]

This patch set implements firmware-assisted dump support for kdump
service. Firmware-assisted dump support depends on  existing kdump
infrastructure (kdump scripts)  present  in userland to  save dump
to the disk. Though existing kdump script will work seemlessly, it
still needs to  modified to make it aware of presense of firmware-
assisted dump feature during service start and stop. These changes
are tested successfully on a power box with fedora19.

---

Hari Bathini (6):
      kdump: Modify status() routine to check for firmware-assisted dump
      kdump: Modify kdump script to start the firmware assisted dump.
      kdump: Modify kdump script to stop firmware assisted dump
      kdump: Take a backup of original default initrd before rebuilding.
      kdump: Rebuild default initrd for firmware assisted dump
      kdump: Check for /proc/vmcore existence before capturing the vmcore.


 dracut-kdump.sh |    3 +
 kdumpctl        |  181 ++++++++++++++++++++++++++++++++++++++++++++++++++-----
 2 files changed, 169 insertions(+), 15 deletions(-)

-- 
- Hari

[PATCH 1/6] kdump: Modify status() routine to check for firmware-assisted dump

[Hari Bathini]

This patch enables kdump script to check if firmware-assisted dump is
enabled or not by reading value from '/sys/kernel/fadump_enabled'.

Modify status() routine to check if firmware assisted dump is enabled
or not by  reading value from  '/sys/kernel/fadump_enabled' file.  If
enabled and value from '/sys/kernel/fadump_registered' file is set to
'1' then return status=0 else return status=1.

    0  <= Firmware assisted is enabled and running
    1  <= Firmware assisted is enabled but not running

Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
---
 kdumpctl |   32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/kdumpctl b/kdumpctl
index 46ae633..1255089 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -9,6 +9,8 @@ MKDUMPRD="/sbin/mkdumprd -f"
 SAVE_PATH=/var/crash
 SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
 DUMP_TARGET=""
+FADUMP_ENABLED_SYS_NODE="/sys/kernel/fadump_enabled"
+FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
 
 . /lib/kdump/kdump-lib.sh
 
@@ -358,8 +360,38 @@ function propagate_ssh_key()
 		
 }
 
+function is_fadump_capable()
+{
+	# Check if firmware-assisted dump is enabled
+	# if yes, check fadump status Otherwise fallback to kdump check
+	if [ -f $FADUMP_ENABLED_SYS_NODE ] && \
+			[ -f $FADUMP_REGISTER_SYS_NODE ]
+	then
+		rc=`cat $FADUMP_ENABLED_SYS_NODE`
+		[ $rc -eq 1 ] && return 0
+	fi
+	return 1
+}
+
+function is_fadump_registered()
+{
+	# Check if firmware-assisted has been registered.
+	rc=`cat $FADUMP_REGISTER_SYS_NODE`
+	[ $rc -eq 1 ] && return 0
+	return 1
+}
+
 function status()
 {
+	# Check if firmware-assisted dump is enabled
+	# if yes, check fadump status Otherwise fallback to kdump check
+	if is_fadump_capable; then
+		if is_fadump_registered; then
+			return 0
+		fi
+		return 1
+	fi
+
 	if [ ! -e /sys/kernel/kexec_crash_loaded ]
 	then
 		return 2

[PATCH 1/6] kdump: Modify status() routine to check for firmware-assisted dump

[Vivek Goyal]

On Tue, Jan 21, 2014 at 10:47:59PM +0530, Hari Bathini wrote:
>  This patch enables kdump script to check if firmware-assisted dump
> is
>  enabled or not by reading value from '/sys/kernel/fadump_enabled'.
>  
>  Modify status() routine to check if firmware assisted dump is enabled
>  or not by  reading value from  '/sys/kernel/fadump_enabled' file.  If
>  enabled and value from '/sys/kernel/fadump_registered' file is set to
>  '1' then return status=0 else return status=1.
>  
>      0  <= Firmware assisted is enabled and running
>      1  <= Firmware assisted is enabled but not running
>  
>  Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
>  ---
>   kdumpctl |   32 ++++++++++++++++++++++++++++++++
>   1 file changed, 32 insertions(+)
>  
>  diff --git a/kdumpctl b/kdumpctl
>  index 46ae633..1255089 100755
>  --- a/kdumpctl
>  +++ b/kdumpctl
>  @@ -9,6 +9,8 @@ MKDUMPRD="/sbin/mkdumprd -f"
>   SAVE_PATH=/var/crash
>   SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
>   DUMP_TARGET=""
>  +FADUMP_ENABLED_SYS_NODE="/sys/kernel/fadump_enabled"
>  +FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
>   
>   . /lib/kdump/kdump-lib.sh
>   
>  @@ -358,8 +360,38 @@ function propagate_ssh_key()
>   		
>   }
>   
>  +function is_fadump_capable()
>  +{
>  +	# Check if firmware-assisted dump is enabled
>  +	# if yes, check fadump status Otherwise fallback to kdump check
>  +	if [ -f $FADUMP_ENABLED_SYS_NODE ] && \
>  +			[ -f $FADUMP_REGISTER_SYS_NODE ]
>  +	then
>  +		rc=`cat $FADUMP_ENABLED_SYS_NODE`
>  +		[ $rc -eq 1 ] && return 0
>  +	fi
>  +	return 1
>  +}
>  +
>  +function is_fadump_registered()
>  +{
>  +	# Check if firmware-assisted has been registered.
>  +	rc=`cat $FADUMP_REGISTER_SYS_NODE`
>  +	[ $rc -eq 1 ] && return 0
>  +	return 1
>  +}
>  +
>   function status()
>   {
>  +	# Check if firmware-assisted dump is enabled
>  +	# if yes, check fadump status Otherwise fallback to kdump check
>  +	if is_fadump_capable; then
>  +		if is_fadump_registered; then
>  +			return 0
>  +		fi
>  +		return 1
>  +	fi 
What's the difference between fadump cabable and fadump enabled?

So if a machine is fadump capable, we always expect it to use fadump
only?

Thanks
Vivek

[PATCH 1/6] kdump: Modify status() routine to check for firmware-assisted dump

[Hari Bathini]

On 02/05/2014 11:48 PM, Vivek Goyal wrote:
>  On Tue, Jan 21, 2014 at 10:47:59PM +0530, Hari Bathini wrote:
> > This patch enables kdump script to check if firmware-assisted dump is
> > enabled or not by reading value from '/sys/kernel/fadump_enabled'.
> >
> > Modify status() routine to check if firmware assisted dump is enabled
> > or not by  reading value from  '/sys/kernel/fadump_enabled' file.  If
> > enabled and value from '/sys/kernel/fadump_registered' file is set to
> > '1' then return status=0 else return status=1.
> >
> >      0  <= Firmware assisted is enabled and running
> >      1  <= Firmware assisted is enabled but not running
> >
> > Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
> > ---
> >   kdumpctl |   32 ++++++++++++++++++++++++++++++++
> >   1 file changed, 32 insertions(+)
> >
> > diff --git a/kdumpctl b/kdumpctl
> > index 46ae633..1255089 100755
> > --- a/kdumpctl
> > +++ b/kdumpctl
> > @@ -9,6 +9,8 @@ MKDUMPRD="/sbin/mkdumprd -f"
> >   SAVE_PATH=/var/crash
> >   SSH_KEY_LOCATION="/root/.ssh/kdump_id_rsa"
> >   DUMP_TARGET=""
> > +FADUMP_ENABLED_SYS_NODE="/sys/kernel/fadump_enabled"
> > +FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
> >   
> >   . /lib/kdump/kdump-lib.sh
> >   
> > @@ -358,8 +360,38 @@ function propagate_ssh_key()
> >   		
> >   }
> >   
> > +function is_fadump_capable()
> > +{
> > +	# Check if firmware-assisted dump is enabled
> > +	# if yes, check fadump status Otherwise fallback to kdump check
> > +	if [ -f $FADUMP_ENABLED_SYS_NODE ] && \
> > +			[ -f $FADUMP_REGISTER_SYS_NODE ]
> > +	then
> > +		rc=`cat $FADUMP_ENABLED_SYS_NODE`
> > +		[ $rc -eq 1 ] && return 0
> > +	fi
> > +	return 1
> > +}
> > +
> > +function is_fadump_registered()
> > +{
> > +	# Check if firmware-assisted has been registered.
> > +	rc=`cat $FADUMP_REGISTER_SYS_NODE`
> > +	[ $rc -eq 1 ] && return 0
> > +	return 1
> > +}
> > +
> >   function status()
> >   {
> > +	# Check if firmware-assisted dump is enabled
> > +	# if yes, check fadump status Otherwise fallback to kdump check
> > +	if is_fadump_capable; then
> > +		if is_fadump_registered; then
> > +			return 0
> > +		fi
> > +		return 1
> > +	fi
>  What's the difference between fadump cabable and fadump enabled?
>
>  So if a machine is fadump capable, we always expect it to use fadump
>  only? 
A fadump capable machine can use either fadump or kdump.
fadump can be enabled by setting "fadump" kernel parameter to "on",
else 
we fall-back to kdump.

Thanks
Hari

[PATCH 2/6] kdump: Modify kdump script to start the firmware assisted dump.

[Hari Bathini]

During service kdump start, if firmware assisted dump is not enabled then
fallback to starting of existing kexec based kdump.  If firmware assisted
is enabled but not running, then start firmware assisted dump by echo'ing
1 to '/sys/kernel/fadump_registered' file.

Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
---
 kdumpctl |   18 +++++++++++++++++-
 1 file changed, 17 insertions(+), 1 deletion(-)

diff --git a/kdumpctl b/kdumpctl
index 1255089..84df073 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -506,6 +506,18 @@ selinux_relabel()
 	done
 }
 
+function start_fadump()
+{
+	echo 1 > $FADUMP_REGISTER_SYS_NODE
+	if is_fadump_registered; then
+		echo "Starting firmware assisted dump: [OK]"
+		return 0
+	else
+		echo "Starting firmware assisted dump: [FAILED]"
+		return 1
+	fi
+}
+
 function start()
 {
 	check_config
@@ -547,7 +559,11 @@ function start()
 		echo "Starting kdump: [FAILED]"
 		return 1
 	fi
-	load_kdump
+	if is_fadump_capable; then
+		start_fadump
+	else
+		load_kdump
+	fi
 	if [ $? != 0 ]; then
 		echo "Starting kdump: [FAILED]"
 		return 1

[PATCH 3/6] kdump: Modify kdump script to stop firmware assisted dump

[Hari Bathini]

During service kdump stop, if firmware assisted dump is enabled
and running,  then stop firmware assisted dump by echo'ing 0 to
'/sys/kernel/fadump_registered' file.

Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
---
 kdumpctl |   19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/kdumpctl b/kdumpctl
index 84df073..41e4c69 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -572,8 +572,27 @@ function start()
 	echo "Starting kdump: [OK]"
 }
 
+function stop_fadump()
+{
+	is_fadump_registered && echo 0 > $FADUMP_REGISTER_SYS_NODE
+	if is_fadump_registered; then
+		echo "fadump: failed to un-register firmware assisted dump"
+		echo "Stopping kdump: [FAILED]"
+		return 1
+	else
+		echo "fadump: un-register firmware assisted dump"
+		echo "Stopping kdump: [OK]"
+		return 0
+	fi
+}
+
 function stop()
 {
+	if is_fadump_capable; then
+		stop_fadump
+		return $?
+	fi
+
 	$KEXEC -p -u 2>/dev/null
 	if [ $? == 0 ]; then
 		echo "kexec: unloaded kdump kernel"

[PATCH 4/6] kdump: Take a backup of original default initrd before rebuilding.

[Hari Bathini]

Take a backup of original initrd when fadump is used first time or
when user has switched from kdump to fadump. This will allow us to
fall back to original initrd  when kdump  service fails to rebuild
the fadump ready  default initrd. Also, if the user  switches from
fadump to kdump, then the  original initrd  will  be restored when
kdump script is run first time after the switch.

Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
Signed-off-by: Hari Bathini <hbathini(a)linux.vnet.ibm.com&gt;
---
 kdumpctl |   80 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 71 insertions(+), 9 deletions(-)

diff --git a/kdumpctl b/kdumpctl
index 41e4c69..f4760b5 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -15,6 +15,7 @@ FADUMP_REGISTER_SYS_NODE="/sys/kernel/fadump_registered"
 . /lib/kdump/kdump-lib.sh
 
 standard_kexec_args="-p"
+declare -i image_time
 
 if [ -f /etc/sysconfig/kdump ]; then
 	. /etc/sysconfig/kdump
@@ -70,6 +71,10 @@ function save_core()
 
 function rebuild_initrd()
 {
+	if is_fadump_capable; then
+		backup_default_initrd
+	fi
+
 	$MKDUMPRD $kdump_initrd $kdump_kver
 	if [ $? != 0 ]; then
 		echo "mkdumprd: failed to make kdump initrd" >&2
@@ -99,6 +104,65 @@ function check_executable()
 	done
 }
 
+function backup_default_initrd()
+{
+	# Check if backup initrd is already present. If not, then
+	# this is the first time fadump is being used OR user
+	# has switched from kdump to fadump.
+	# Take a backup of the original default initrd before
+	# we rebuild default initrd for fadump support.
+	if [ ! -e $default_initrd_bak ];then
+		echo "Backing up default initrd"
+		cp $default_initrd $default_initrd_bak
+		sync
+	fi
+}
+
+function check_fadump()
+{
+	default_initrd_bak="$default_initrd.default.bak"
+	if is_fadump_capable; then
+		if [ -e $kdump_initrd ];then
+                        # This means user has switched from kdump to fadump.
+                        # Remove kdump initrd which is no longer needed
+			rm -f $kdump_initrd
+                fi
+	else
+		if [ -e $default_initrd_bak ];then
+			# !fadump and original initrd backup file exists.
+			# This means user has switched from fadump to kdump.
+			# Restore the original default initrd.
+			mv $default_initrd_bak $default_initrd
+			sync
+		fi
+	fi
+}
+
+function find_initrd_image_time()
+{
+	image_time=0
+
+	# Check to see if dependent files have been modified
+	# since last build of the image file
+	if [ -f $kdump_initrd ]; then
+		image_time=`stat -c "%Y" $kdump_initrd 2>/dev/null`
+		return
+	else
+		# if fadump is not used, image_time=0
+		if ! is_fadump_capable; then
+			return
+		fi
+	fi
+
+	# If this is the first time we are using fadump then let image_time
+	# be zero to force rebuild intital initrd. The non-existance of backup
+	# initrd means this is the first time fadump is being used. if exists
+	# then return the image time of default initrd.
+	if [ -e $default_initrd_bak ]; then
+		image_time=`stat -c "%Y" $default_initrd 2>/dev/null`
+	fi
+}
+
 function check_config()
 {
 	local nr
@@ -146,7 +210,9 @@ function check_rebuild()
 	fi
 
 	kdump_kernel="${KDUMP_BOOTDIR}/${KDUMP_IMG}-${kdump_kver}${KDUMP_IMG_EXT}"
+	default_initrd="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}.img"
 	kdump_initrd="${KDUMP_BOOTDIR}/initramfs-${kdump_kver}kdump.img"
+	check_fadump
 
 	_force_rebuild=`grep ^force_rebuild $KDUMP_CONFIG_FILE 2>/dev/null`
 	if [ $? -eq 0 ]; then
@@ -157,17 +223,13 @@ function check_rebuild()
 		fi
 	fi
 
-	#will rebuild every time if extra_modules are specified
+	# Will rebuild every time if extra_modules are specified
 	extra_modules=`grep ^extra_modules $KDUMP_CONFIG_FILE`
 	[ -n "$extra_modules" ] && force_rebuild="1"
 
-	#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`
-	else
-		image_time=0
-	fi
+	# Find initrd image time based on whether dependent files have been
+	# modified since last build of the image file
+	find_initrd_image_time
 
 	EXTRA_BINS=`grep ^kdump_post $KDUMP_CONFIG_FILE | cut -d\  -f2`
 	CHECK_FILES=`grep ^kdump_pre $KDUMP_CONFIG_FILE | cut -d\  -f2`
@@ -191,7 +253,7 @@ function check_rebuild()
 	elif [ "$force_rebuild" != "0" ]; then
 		echo -n "Force rebuild $kdump_initrd"; echo
 	elif [ -n "$modified_files" ]; then
-		echo "Detected change(s) the following file(s):"
+		echo "Detected change(s) in the following file(s):"
 		echo -n "  "; echo "$modified_files" | sed 's/\s/\n  /g'
 	else
 		return 0

[PATCH 4/6] kdump: Take a backup of original default initrd before rebuilding.

[Vivek Goyal]

On Tue, Jan 21, 2014 at 10:48:20PM +0530, Hari Bathini wrote:

[..]
>  +function backup_default_initrd()
>  +{
>  +	# Check if backup initrd is already present. If not, then
>  +	# this is the first time fadump is being used OR user
>  +	# has switched from kdump to fadump.
>  +	# Take a backup of the original default initrd before
>  +	# we rebuild default initrd for fadump support.
>  +	if [ ! -e $default_initrd_bak ];then
>  +		echo "Backing up default initrd"
>  +		cp $default_initrd $default_initrd_bak
>  +		sync
>  +	fi
>  +}
>  +
>  +function check_fadump()
>  +{ 
I think this function should be named better. Say handle_dump_mode_switch().

In general there are too many checks for what state we are in, whether
we have transitioned modes (from fadump to kdump or vice versa).

I think we should write a top level function where we should do all
this processing, instead of it being sprinkled all over. 

That is determine in what mode kdump service is supposed to start, kdump
or fadump and store that state in a variable, say "dump_mode". And use
that variable in rest of the places to take kdump or fadump specific
actions.

So your top level function could be say, determine_dump_mode(). And
with-in that function you could also handle mode transition and call
handle_dump_mode_switch().

Once this is taken care of reading up rest of the code will become little
easier.

Thanks
Vivek

[PATCH 5/6] kdump: Rebuild default initrd for firmware assisted dump

[Hari Bathini]

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 default 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.  Once kdump (fadump) initrd is  successfully rebuild from the
default  initrd image, this patch replaces  the default initrd image
with the newly built initrd.

check_config()
            -> rebuild_initrd()
                     Rebuild default initrd with fadump support
            -> handle_fadump_initrd()
                     Replace default with initrd built for fadump.

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.

Dracut patch  that introduces '--rebuild' option is posted upstream,
awaiting approval. Link for reference:
http://www.spinics.net/lists/linux-initramfs/msg03495.html

Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
Signed-off-by: Hari Bathini <hbathini(a)linux.vnet.ibm.com&gt;
---
 kdumpctl |   36 +++++++++++++++++++++++++++++-------
 1 file changed, 29 insertions(+), 7 deletions(-)

diff --git a/kdumpctl b/kdumpctl
index f4760b5..976dfe8 100755
--- a/kdumpctl
+++ b/kdumpctl
@@ -72,13 +72,25 @@ function save_core()
 function rebuild_initrd()
 {
 	if is_fadump_capable; then
+		if [ ! -s "$default_initrd" ]; then
+			echo "No default initrd found to rebuild for fadump support!"
+			return 1
+		fi
 		backup_default_initrd
-	fi
-
-	$MKDUMPRD $kdump_initrd $kdump_kver
-	if [ $? != 0 ]; then
-		echo "mkdumprd: failed to make kdump initrd" >&2
-		return 1
+		echo "Rebuilding $default_initrd with fadump support"
+		$MKDUMPRD --rebuild $default_initrd --kver $kdump_kver
+		if [ $? != 0 ]; then
+			echo "mkdumprd: failed to make initrd with fadump support" >&2
+			restore_default_initrd
+			return 1
+		fi
+	else
+		echo "Rebuilding $kdump_initrd"
+		$MKDUMPRD $kdump_initrd $kdump_kver
+		if [ $? != 0 ]; then
+			echo "mkdumprd: failed to make kdump initrd" >&2
+			return 1
+		fi
 	fi
 }
 
@@ -138,6 +150,17 @@ function check_fadump()
 	fi
 }
 
+function restore_default_initrd()
+{
+	# We have failed to rebuild initrd for fadump support.
+	# Restore the original default initrd.
+	if [ -f $default_initrd_bak ];then
+		echo "Restored default initrd"
+		mv $default_initrd_bak $default_initrd
+		sync
+	fi
+}
+
 function find_initrd_image_time()
 {
 	image_time=0
@@ -259,7 +282,6 @@ function check_rebuild()
 		return 0
 	fi
 
-	echo "Rebuilding $kdump_initrd"
 	rebuild_initrd
 	return $?
 }

[PATCH 5/6] kdump: Rebuild default initrd for firmware assisted dump

[Vivek Goyal]

On Tue, Jan 21, 2014 at 10:48:28PM +0530, Hari Bathini wrote:
>  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 default 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.  Once kdump (fadump) initrd is  successfully rebuild from the
>  default  initrd image, this patch replaces  the default initrd image
>  with the newly built initrd.
>  
>  check_config()
>              -> rebuild_initrd()
>                       Rebuild default initrd with fadump support
>              -> handle_fadump_initrd()
>                       Replace default with initrd built for fadump. 
I think above description is wrong. You seem to be doing reverse. Directly
rebuilding initrd and if it fails, replace it with backup copy.

Can you please fix changelogs.

[..]
>  diff --git a/kdumpctl b/kdumpctl
>  index f4760b5..976dfe8 100755
>  --- a/kdumpctl
>  +++ b/kdumpctl
>  @@ -72,13 +72,25 @@ function save_core()
>   function rebuild_initrd()
>   {
>   	if is_fadump_capable; then
>  +		if [ ! -s "$default_initrd" ]; then
>  +			echo "No default initrd found to rebuild for fadump support!"
>  +			return 1
>  +		fi
>   		backup_default_initrd
>  -	fi
>  -
>  -	$MKDUMPRD $kdump_initrd $kdump_kver
>  -	if [ $? != 0 ]; then
>  -		echo "mkdumprd: failed to make kdump initrd" >&2
>  -		return 1
>  +		echo "Rebuilding $default_initrd with fadump support"
>  +		$MKDUMPRD --rebuild $default_initrd --kver $kdump_kver
>  +		if [ $? != 0 ]; then
>  +			echo "mkdumprd: failed to make initrd with fadump support" >&2
>  +			restore_default_initrd
>  +			return 1
>  +		fi
>  +	else
>  +		echo "Rebuilding $kdump_initrd"
>  +		$MKDUMPRD $kdump_initrd $kdump_kver
>  +		if [ $? != 0 ]; then
>  +			echo "mkdumprd: failed to make kdump initrd" >&2
>  +			return 1
>  +		fi 
How about splitting it in two functions. Something like.

rebuild_initrd() {
	if (dump_mode == kdump)
		rebuild_kdump_initrd()
	else
		rebuild_fadump_initrd()
	fi
}

Thanks
Vivek

[PATCH 6/6] kdump: Check for /proc/vmcore existence before capturing the vmcore.

[Hari Bathini]

The script dracut-kdump.sh is  responsible for capturing vmcore during
second kernel boot.  Currently this  script  gets installed into kdump
initrd as part of kdumpbase dracut module. Since it's always installed
into kdump initrd, this script assumes that '/proc/vmcore' will always
be present when it is invoked.

With fadump support, 'dracut-kdump.sh' script also gets installed into
default initrd to capture  vmcore generated by firmware assisted dump.
Thus in fadump case, the  same initrd is  going to be used for  normal
boot as well as boot after system crash. Hence a  check is required to
see if '/proc/vmcore' file  exists before  executing  steps to capture
vmcore. This check will help to bypass the vmcore capture steps during
normal boot process.

Signed-off-by: Mahesh Salgaonkar <mahesh(a)linux.vnet.ibm.com&gt;
Signed-off-by: Hari Bathini <hbathini(a)linux.vnet.ibm.com&gt;
---
 dracut-kdump.sh |    3 +++
 1 file changed, 3 insertions(+)

diff --git a/dracut-kdump.sh b/dracut-kdump.sh
index 4d8616f..ce977d9 100755
--- a/dracut-kdump.sh
+++ b/dracut-kdump.sh
@@ -1,5 +1,8 @@
 #!/bin/sh
 
+# continue only if /proc/vmcore is present.
+[ ! -f /proc/vmcore ] && return
+
 exec &> /dev/console
 . /lib/dracut-lib.sh
 . /lib/kdump-lib.sh

[Vivek Goyal]

On Tue, Jan 21, 2014 at 10:47:52PM +0530, Hari Bathini wrote:
>  This patch set implements firmware-assisted dump support for kdump
>  service. Firmware-assisted dump support depends on  existing kdump
>  infrastructure (kdump scripts)  present  in userland to  save dump
>  to the disk. Though existing kdump script will work seemlessly, it
>  still needs to  modified to make it aware of presense of firmware-
>  assisted dump feature during service start and stop. These changes
>  are tested successfully on a power box with fedora19. 
I have some general comments.

- Can you please write a .txt file say fadump-powerpc-howto.txt and put
  some details about how fadump works, how to configure it etc. For
  details you can refer to kernel Documentation/powerpc/fadump*.txt file.
  I am more interested here in putting details about how initrd is
  generated and managed etc.

- Please put details about how user can switch between kdump and fadump
  modes.

- I did not see any code which does not reboot machine after capturing
  dump.

- How would you handle "default" in kdump.conf. I think all these defaults
  don't make sense in case of fadump? IOW, if dump capturing fails what
  would you do?  Continue normal boot?

  IF yes, we need to put all these details in fadump howto file.

- If "default" are ignored in fadump mode, we might want to give a warning
  to user about it.

- Are you still saving dump from initramfs context? Why?

Thanks
Vivek