[PATCH V4 dracut 0/3] Install kernel module for active watchdog

[PATCH V4 dracut 0/3] Install kernel module for active watchdog

[Pratyush Anand]

Changes since V3:
-- Incorporated changes suggested by Harald for V2 patches

Changes since V2:
-- Added one more patch to update rd.driver.pre with watchdog module name,
so that they are loaded into kernel as early as possible.
-- Removed creation of tmp/active-watchdogs. modinfo will be helpful for
kexec-tools.
-- Now we add modules for active watchdog in hostonly mode and modules for
all watchdog in no-hostonly mode.

Changes since RFC:
-- Added one more patch to take care that dracut does not add watchdog
hooks when systemd module is included. In that case systemd daemon will
manage watchdog for kicking.
-- Removed --nowdt argument. User can use -o or --omit when wathdog module
is not needed. Thanks Harald for this suggestion.
-- Now I also do not check for "hostonly" to add modules for active
watchdog. It seems reasonable to add kernel watchdog modules whenever,
dracut watchdog module has been added.


Pratyush Anand (3):
  watchdog: Do not add hooks if systemd module is included
  watchdog: install module for active watchdog
  watchdog: ensure that module is loaded as early as possible

Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Don Zickus <dzickus-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>

 modules.d/04watchdog/module-setup.sh | 38 ++++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

-- 
2.5.0

[PATCH V4 dracut 1/3] watchdog: Do not add hooks if systemd module is included

[Pratyush Anand]

When systemd is present, let it manage watchdog feed.

Signed-off-by: Pratyush Anand <panand-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Don Zickus <dzickus-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 modules.d/04watchdog/module-setup.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/modules.d/04watchdog/module-setup.sh b/modules.d/04watchdog/module-setup.sh
index 576c589c198d..7ec757aec032 100755
--- a/modules.d/04watchdog/module-setup.sh
+++ b/modules.d/04watchdog/module-setup.sh
@@ -12,6 +12,11 @@ depends() {
 
 # called by dracut
 install() {
+    # Do not add watchdog hooks if systemd module is included
+    # In that case, systemd will manage watchdog kick
+    if dracut_module_included "systemd"; then
+	    return
+    fi
     inst_hook cmdline   00 "$moddir/watchdog.sh"
     inst_hook cmdline   50 "$moddir/watchdog.sh"
     inst_hook pre-trigger 00 "$moddir/watchdog.sh"
-- 
2.5.0

[PATCH V4 dracut 2/3] watchdog: install module for active watchdog

[Pratyush Anand]

Recently following patches have been added in upstream Linux kernel, which
(1) fixes parent of watchdog_device so that
/sys/class/watchdog/watchdogn/device is populated. (2) adds some sysfs
device attributes so that different watchdog status can be read.

http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6551881c86c791237a3bebf11eb3bd70b60ea782
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=906d7a5cfeda508e7361f021605579a00cd82815
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=33b711269ade3f6bc9d9d15e4343e6fa922d999b

With the above support, now we can find out whether a watchdog is active or
not. We can also find out the driver/module responsible for that watchdog
device.

Proposed patch uses above support and then adds module of active watchdog
in initramfs generated by dracut for hostonly mode. Kernel module for
inactive watchdog will be added as well for none hostonly mode.

When an user does not want to add kernel module, then one should exclude
complete dracut watchdog module with --omit.

Testing:
-- When watchdog is active watchdog modules were added
	# cat /sys/class/watchdog/watchdog0/identity
	iTCO_wdt
	# cat /sys/class/watchdog/watchdog0/state
	active
	# dracut --hostonly initramfs-test.img -a watchdog
	# lsinitrd initramfs-test.img | grep iTCO
	-rw-r--r--   1 root     root         9100 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_vendor_support.ko
	-rw-r--r--   1 root     root        19252 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_wdt.ko

-- When watchdog is inactive then watchdog modules were not added
	# cat /sys/class/watchdog/watchdog0/state
	inactive
	# dracut --hostonly initramfs-test.img -a watchdog
	# lsinitrd initramfs-test.img | grep iTCO

-- When watchdog is inactive, but no hostonly mode, watchdog modules were added
	# cat /sys/class/watchdog/watchdog0/state
	inactive
	# dracut --no-hostonly initramfs-test.img -a watchdog
	# lsinitrd initramfs-test.img | grep iTCO
	-rw-r--r--   1 root     root         9100 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_vendor_support.ko
	-rw-r--r--   1 root     root        19252 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_wdt.ko

Signed-off-by: Pratyush Anand <panand-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Don Zickus <dzickus-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 modules.d/04watchdog/module-setup.sh | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/modules.d/04watchdog/module-setup.sh b/modules.d/04watchdog/module-setup.sh
index 7ec757aec032..0ffaa9658502 100755
--- a/modules.d/04watchdog/module-setup.sh
+++ b/modules.d/04watchdog/module-setup.sh
@@ -32,3 +32,31 @@ install() {
     inst_multiple -o wdctl
 }
 
+installkernel() {
+    [[ -d /sys/class/watchdog/ ]] || return
+    for dir in /sys/class/watchdog/*; do
+	    [[ -d "$dir" ]] || continue
+	    [[ -f "$dir/state" ]] || continue
+	    active=$(< "$dir/state")
+	    ! [[ $hostonly ]] || [[ "$active" =  "active" ]] || continue
+	    # device/modalias will return driver of this device
+	    wdtdrv=$(< "$dir/device/modalias")
+	    # There can be more than one module represented by same
+	    # modalias. Currently load all of them.
+	    # TODO: Need to find a way to avoid any unwanted module
+	    # represented by modalias
+	    wdtdrv=$(modprobe -R $wdtdrv)
+	    instmods $wdtdrv
+	    # however in some cases, we also need to check that if there is
+	    # a specific driver for the parent bus/device.  In such cases
+	    # we also need to enable driver for parent bus/device.
+	    wdtppath=$(readlink -f "$dir/device/..")
+	    while [ -f "$wdtppath/modalias" ]
+	    do
+		    wdtpdrv=$(< "$wdtppath/modalias")
+		    wdtpdrv=$(modprobe -R $wdtpdrv)
+		    instmods $wdtpdrv
+		    wdtppath=$(readlink -f "$wdtppath/..")
+	    done
+    done
+}
-- 
2.5.0

Re: [PATCH V4 dracut 2/3] watchdog: install module for active watchdog

[Dave Young]

Hi, Pratyush

On 03/08/16 at 02:14pm, Pratyush Anand wrote:
> Recently following patches have been added in upstream Linux kernel, which
> (1) fixes parent of watchdog_device so that
> /sys/class/watchdog/watchdogn/device is populated. (2) adds some sysfs
> device attributes so that different watchdog status can be read.
> 
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6551881c86c791237a3bebf11eb3bd70b60ea782
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=906d7a5cfeda508e7361f021605579a00cd82815
> http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=33b711269ade3f6bc9d9d15e4343e6fa922d999b
> 
> With the above support, now we can find out whether a watchdog is active or
> not. We can also find out the driver/module responsible for that watchdog
> device.
> 
> Proposed patch uses above support and then adds module of active watchdog
> in initramfs generated by dracut for hostonly mode. Kernel module for
> inactive watchdog will be added as well for none hostonly mode.
> 
> When an user does not want to add kernel module, then one should exclude
> complete dracut watchdog module with --omit.
> 
> Testing:
> -- When watchdog is active watchdog modules were added
> 	# cat /sys/class/watchdog/watchdog0/identity
> 	iTCO_wdt
> 	# cat /sys/class/watchdog/watchdog0/state
> 	active
> 	# dracut --hostonly initramfs-test.img -a watchdog
> 	# lsinitrd initramfs-test.img | grep iTCO
> 	-rw-r--r--   1 root     root         9100 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_vendor_support.ko
> 	-rw-r--r--   1 root     root        19252 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_wdt.ko
> 
> -- When watchdog is inactive then watchdog modules were not added
> 	# cat /sys/class/watchdog/watchdog0/state
> 	inactive
> 	# dracut --hostonly initramfs-test.img -a watchdog
> 	# lsinitrd initramfs-test.img | grep iTCO
> 
> -- When watchdog is inactive, but no hostonly mode, watchdog modules were added
> 	# cat /sys/class/watchdog/watchdog0/state
> 	inactive
> 	# dracut --no-hostonly initramfs-test.img -a watchdog
> 	# lsinitrd initramfs-test.img | grep iTCO
> 	-rw-r--r--   1 root     root         9100 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_vendor_support.ko
> 	-rw-r--r--   1 root     root        19252 Feb 24 09:19 usr/lib/modules/.../kernel/drivers/watchdog/iTCO_wdt.ko
> 
> Signed-off-by: Pratyush Anand <panand-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Don Zickus <dzickus-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  modules.d/04watchdog/module-setup.sh | 28 ++++++++++++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/modules.d/04watchdog/module-setup.sh b/modules.d/04watchdog/module-setup.sh
> index 7ec757aec032..0ffaa9658502 100755
> --- a/modules.d/04watchdog/module-setup.sh
> +++ b/modules.d/04watchdog/module-setup.sh
> @@ -32,3 +32,31 @@ install() {
>      inst_multiple -o wdctl
>  }
>  
> +installkernel() {
> +    [[ -d /sys/class/watchdog/ ]] || return
> +    for dir in /sys/class/watchdog/*; do
> +	    [[ -d "$dir" ]] || continue
> +	    [[ -f "$dir/state" ]] || continue
> +	    active=$(< "$dir/state")
> +	    ! [[ $hostonly ]] || [[ "$active" =  "active" ]] || continue

Even if for devices which is not active it is still a hostonly device because
it being detected by kernel running on the host? 

But I will not stick to this issue, I'm fine if Harald is ok with it because I do
not know how to handle non hostonly in a proper way ..

Thanks
Dave

Re: [PATCH V4 dracut 2/3] watchdog: install module for active watchdog

[Pratyush Anand]

Hi Harald,

On 08/03/2016:05:29:12 PM, Dave Young wrote:
> On 03/08/16 at 02:14pm, Pratyush Anand wrote:
> > +	    active=$(< "$dir/state")
> > +	    ! [[ $hostonly ]] || [[ "$active" =  "active" ]] || continue
> 
> Even if for devices which is not active it is still a hostonly device because
> it being detected by kernel running on the host? 
> 
> But I will not stick to this issue, I'm fine if Harald is ok with it because I do
> not know how to handle non hostonly in a proper way ..

Please let me know if you have any further input for these patches. Otherwise, I
will send a V5 with the update in patch 3/3 incorporating Dave's comment for
change in Watchdog command line file name.

~Pratyush

[PATCH V4 dracut 3/3] watchdog: ensure that module is loaded as early as possible

[Pratyush Anand]

It is expected that a watchdog module will disable an active watchdog when
its probe is called ie, when it is loaded. So an early load of the module
will help to disable it earlier.
This can be helpful in some corner cases where kdump and watchdog daemon
both are active.

Testing:
    -- When watchdog kernel modules were added
	# dracut --no-hostonly initramfs-test.img -a watchdog
	# lsinitrd initramfs-test.img -f etc/cmdline.d/04-watchdog.conf
 	rd.driver.pre=iTCO_wdt,lpc_ich,

Signed-off-by: Pratyush Anand <panand-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Don Zickus <dzickus-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
Cc: Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
 modules.d/04watchdog/module-setup.sh | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/modules.d/04watchdog/module-setup.sh b/modules.d/04watchdog/module-setup.sh
index 0ffaa9658502..d99e5b33de44 100755
--- a/modules.d/04watchdog/module-setup.sh
+++ b/modules.d/04watchdog/module-setup.sh
@@ -34,6 +34,7 @@ install() {
 
 installkernel() {
     [[ -d /sys/class/watchdog/ ]] || return
+    wdtcmdline=""
     for dir in /sys/class/watchdog/*; do
 	    [[ -d "$dir" ]] || continue
 	    [[ -f "$dir/state" ]] || continue
@@ -47,6 +48,7 @@ installkernel() {
 	    # represented by modalias
 	    wdtdrv=$(modprobe -R $wdtdrv)
 	    instmods $wdtdrv
+	    wdtcmdline="$wdtcmdline$(echo $wdtdrv | tr " " ","),"
 	    # however in some cases, we also need to check that if there is
 	    # a specific driver for the parent bus/device.  In such cases
 	    # we also need to enable driver for parent bus/device.
@@ -56,7 +58,10 @@ installkernel() {
 		    wdtpdrv=$(< "$wdtppath/modalias")
 		    wdtpdrv=$(modprobe -R $wdtpdrv)
 		    instmods $wdtpdrv
+		    wdtcmdline="$wdtcmdline$(echo $wdtpdrv | tr " " ","),"
 		    wdtppath=$(readlink -f "$wdtppath/..")
 	    done
     done
+    # ensure that watchdog module is loaded as early as possible
+    [[ $wdtcmdline = "" ]] || echo "rd.driver.pre=$wdtcmdline" > ${initdir}/etc/cmdline.d/04-watchdog.conf
 }
-- 
2.5.0

Re: [PATCH V4 dracut 3/3] watchdog: ensure that module is loaded as early as possible

[Dracut GitHub Import Bot]

Patchset imported to github.
Pull request:
<https://github.com/haraldh/dracut/compare/master...dracut-mailing-devs:e63d322e2cc3081a616f14f5586998811145931d.1457425628.git.panand%40redhat.com>

Re: [PATCH V4 dracut 3/3] watchdog: ensure that module is loaded as early as possible

[Dave Young]

Hi, Pratyush

On 03/08/16 at 02:14pm, Pratyush Anand wrote:
> It is expected that a watchdog module will disable an active watchdog when
> its probe is called ie, when it is loaded. So an early load of the module
> will help to disable it earlier.
> This can be helpful in some corner cases where kdump and watchdog daemon
> both are active.
> 
> Testing:
>     -- When watchdog kernel modules were added
> 	# dracut --no-hostonly initramfs-test.img -a watchdog
> 	# lsinitrd initramfs-test.img -f etc/cmdline.d/04-watchdog.conf
>  	rd.driver.pre=iTCO_wdt,lpc_ich,
> 
> Signed-off-by: Pratyush Anand <panand-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Dave Young <dyoung-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Don Zickus <dzickus-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> Cc: Harald Hoyer <harald-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
>  modules.d/04watchdog/module-setup.sh | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/modules.d/04watchdog/module-setup.sh b/modules.d/04watchdog/module-setup.sh
> index 0ffaa9658502..d99e5b33de44 100755
> --- a/modules.d/04watchdog/module-setup.sh
> +++ b/modules.d/04watchdog/module-setup.sh
> @@ -34,6 +34,7 @@ install() {
>  
>  installkernel() {
>      [[ -d /sys/class/watchdog/ ]] || return
> +    wdtcmdline=""
>      for dir in /sys/class/watchdog/*; do
>  	    [[ -d "$dir" ]] || continue
>  	    [[ -f "$dir/state" ]] || continue
> @@ -47,6 +48,7 @@ installkernel() {
>  	    # represented by modalias
>  	    wdtdrv=$(modprobe -R $wdtdrv)
>  	    instmods $wdtdrv
> +	    wdtcmdline="$wdtcmdline$(echo $wdtdrv | tr " " ","),"
>  	    # however in some cases, we also need to check that if there is
>  	    # a specific driver for the parent bus/device.  In such cases
>  	    # we also need to enable driver for parent bus/device.
> @@ -56,7 +58,10 @@ installkernel() {
>  		    wdtpdrv=$(< "$wdtppath/modalias")
>  		    wdtpdrv=$(modprobe -R $wdtpdrv)
>  		    instmods $wdtpdrv
> +		    wdtcmdline="$wdtcmdline$(echo $wdtpdrv | tr " " ","),"
>  		    wdtppath=$(readlink -f "$wdtppath/..")
>  	    done
>      done
> +    # ensure that watchdog module is loaded as early as possible
> +    [[ $wdtcmdline = "" ]] || echo "rd.driver.pre=$wdtcmdline" > ${initdir}/etc/cmdline.d/04-watchdog.conf

It is not necessary to use same number as the dracut module "04".
Since it is special we want it being loaded as soon as possible move it to 00-watchdog.conf sound better.

Thanks
Dave

Re: [PATCH V4 dracut 3/3] watchdog: ensure that module is loaded as early as possible

[Pratyush Anand]

Hi Dave,

On 08/03/2016:05:37:38 PM, Dave Young wrote:
> > +    [[ $wdtcmdline = "" ]] || echo "rd.driver.pre=$wdtcmdline" > ${initdir}/etc/cmdline.d/04-watchdog.conf
> 
> It is not necessary to use same number as the dracut module "04".
> Since it is special we want it being loaded as soon as possible move it to 00-watchdog.conf sound better.

OK. Will change.

~Pratyush

Re: [PATCH V4 dracut 0/3] Install kernel module for active watchdog

[Dave Young]

Hi, Pratyush

On 03/08/16 at 02:14pm, Pratyush Anand wrote:
> Changes since V3:
> -- Incorporated changes suggested by Harald for V2 patches
> 
> Changes since V2:
> -- Added one more patch to update rd.driver.pre with watchdog module name,
> so that they are loaded into kernel as early as possible.
> -- Removed creation of tmp/active-watchdogs. modinfo will be helpful for
> kexec-tools.

Kdump still need save a previous added wdt somewhere so that it can rebuild
initrd if necessary. I'm not sure where can we store the state, do you have
some thoughts about it?

Thanks
Dave 

Re: [PATCH V4 dracut 0/3] Install kernel module for active watchdog

[Pratyush Anand]

Hi Dave,

On 08/03/2016:05:34:00 PM, Dave Young wrote:
> On 03/08/16 at 02:14pm, Pratyush Anand wrote:
> > -- Removed creation of tmp/active-watchdogs. modinfo will be helpful for
> > kexec-tools.
> 
> Kdump still need save a previous added wdt somewhere so that it can rebuild
> initrd if necessary. I'm not sure where can we store the state, do you have
> some thoughts about it?

modinfo is able to help out here. See following kexec implementation, which I
still need to cleanup (as per coding style feedback received for dracut
patches), But I have tested it and it works.

https://github.com/pratyushanand/kexec-tools/blob/watchdog_fmaster/kdumpctl#L341

~Pratyush