Hi, All
Now upon failure kdump script might not be called at all and it might not be able to execute default action. It results in a hang.
Because we disable emergency shell and rely on kdump.sh being invoked through dracut-pre-pivot hook. But it might happen that we never call into dracut-pre-pivot hook because certain systemd targets could not reach due to failure in their dependencies. In those cases error handling code does not run and system hangs.
To solve this problem, we need to separate the error handling code from dracut-pre-pivot hook, and every time when a failure shows up, the separated code can be called by the emergency service.
By default systemd provides an emergency service which will drop us into shell every time upon a critical failure. It's very convenient for us to re-use the framework of systemd emergency, because we don't have to touch the other parts of systemd. We can use our own script instead of the default one.
This new scheme will overwrite emergency shell and replace with kdump error handling code. And this code will do the error handling as needed. Now, we will not rely on dracut-pre-pivot hook running always. Instead whenever error happens and it is serious enough that emergency shell needed to run, now kdump error handler will run.
This patchset introduce a new kdump emergency service. It will override the existing emergency.service. When fatal error occurs, this emergency service will be triggered and systemd will isolate to emergency path.
This kdump emergency service can will read kdump.conf and act according to the configired "default action" (reboot/poweroff/halt/shell/dump_to_rootfs).
Along with this patchset, kdump-capture.service is introduced as a service unit to run kdump.sh. When kdump-capture.service fails, systemd will isolate to kdump emergency service. I copied all the dependencies from dracut-pre-pivot.service to kdump-capture.service so that kdump.sh will be called at the correct time window.
v2: Address several comments from Vivek: - split [patch 1] into 1/6 and 2/6 - remove several unnecessary lines in service unit. - modify the description of kdump-capture.service - introduce another kdump lib kdump-lib-2.sh used in 2nd kernel.
V3: Address several comments from Vivek: - update description of [PATCH 1/5] and [PATCH 5/5] - separate the patch of cleanup to kdump-lib-initramfs.sh
V4: Address several comments from Vivek and Dave: - meld the original [PATCH 3/5] into [PATCH 1/5] - add GPL license for kdump-error-handler.service and kdump-capture.service - separate the "x-initrd.mount" and "mount under /sysroot" patch to another patchset
V5: - Rebase on top of the fadump patchset. - Enable dracut-emergency again, but override it with kdump error handler.
V6: - reboot if entering error handler in error handling path - add comments in dracut-kdump-emergency.service - update changelog
WANG Chao (2): Introduce kdump error handling service Introduce kdump capture service
dracut-kdump-capture.service | 30 ++++++++++++++++++++++++++++++ dracut-kdump-emergency.service | 34 ++++++++++++++++++++++++++++++++++ dracut-kdump-error-handler.sh | 18 ++++++++++++++++++ dracut-kdump.sh | 9 ++------- dracut-module-setup.sh | 10 ++++++++-- kdump-lib-initramfs.sh | 34 ++++++++++++++++++++++++++++++---- kexec-tools.spec | 7 ++++++- 7 files changed, 128 insertions(+), 14 deletions(-) create mode 100644 dracut-kdump-capture.service create mode 100644 dracut-kdump-emergency.service create mode 100755 dracut-kdump-error-handler.sh
Now upon failure kdump script might not be called at all and it might not be able to execute default action. It results in a hang.
Because we disable emergency shell and rely on kdump.sh being invoked through dracut-pre-pivot hook. But it might happen that we never call into dracut-pre-pivot hook because certain systemd targets could not reach due to failure in their dependencies. In those cases error handling code does not run and system hangs. For example:
sysroot-var-crash.mount --> initrd-root-fs.target --> initrd.target \ --> dracut-pre-pivot.service --> kdump.sh
If /var/crash mount fails, local-fs.target will not be reached. And then sysinit.target will not be reached, kdump-pre-pivot.service wouldn't run. Finally kdump.sh wouldn't run.
To solve this problem, we need to separate the error handling code from dracut-pre-pivot hook, and every time when a failure shows up, the separated code can be called by the emergency service.
By default systemd provides an emergency service which will drop us into shell every time upon a critical failure. It's very convenient for us to re-use the framework of systemd emergency, because we don't have to touch the other parts of systemd. We can use our own script instead of the default one.
This new scheme will overwrite emergency shell and replace with kdump error handling code. And this code will do the error handling as needed. Now, we will not rely on dracut-pre-pivot hook running always. Instead whenever error happens and it is serious enough that emergency shell needed to run, now kdump error handler will run.
dracut-emergency is also replaced by kdump error handler and it's enabled again all the way down. So all the failure (including systemd and dracut) in 2nd kernel could be captured, and trigger kdump error handler.
Signed-off-by: WANG Chao chaowang@redhat.com --- dracut-kdump-emergency.service | 34 ++++++++++++++++++++++++++++++++++ dracut-kdump-error-handler.sh | 18 ++++++++++++++++++ dracut-kdump.sh | 4 ---- dracut-module-setup.sh | 6 +++++- kdump-lib-initramfs.sh | 34 ++++++++++++++++++++++++++++++---- kexec-tools.spec | 5 ++++- 6 files changed, 91 insertions(+), 10 deletions(-) create mode 100644 dracut-kdump-emergency.service create mode 100755 dracut-kdump-error-handler.sh
diff --git a/dracut-kdump-emergency.service b/dracut-kdump-emergency.service new file mode 100644 index 0000000..6152e78 --- /dev/null +++ b/dracut-kdump-emergency.service @@ -0,0 +1,34 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. + +# This service will be placed in kdump initramfs and replace both the systemd +# emergency service and dracut emergency shell. IOW, any emergency will be +# kick kdump error handler. + +[Unit] +Description=Kdump Error Handler +DefaultDependencies=no +After=systemd-vconsole-setup.service +Wants=systemd-vconsole-setup.service + +[Service] +Environment=HOME=/ +Environment=DRACUT_SYSTEMD=1 +Environment=NEWROOT=/sysroot +WorkingDirectory=/ +ExecStart=/bin/kdump-error-handler.sh +ExecStopPost=-/usr/bin/systemctl --fail --no-block default +Type=oneshot +StandardInput=tty-force +StandardOutput=inherit +StandardError=inherit +KillMode=process +IgnoreSIGPIPE=no + +# Bash ignores SIGTERM, so we send SIGHUP instead, to ensure that bash +# terminates cleanly. +KillSignal=SIGHUP diff --git a/dracut-kdump-error-handler.sh b/dracut-kdump-error-handler.sh new file mode 100755 index 0000000..01a50e0 --- /dev/null +++ b/dracut-kdump-error-handler.sh @@ -0,0 +1,18 @@ +#!/bin/sh + +. /lib/kdump-lib-initramfs.sh + +set -o pipefail +export PATH=$PATH:$KDUMP_SCRIPT_DIR + +# We only allow to enter kdump error handler once. +# If error happens in error handling path and we simply reboot. +if [ -f /kdump-error-handler ]; then + do_final_action +else + > /kdump-error-handler +fi + +get_kdump_confs +do_default_action +do_final_action diff --git a/dracut-kdump.sh b/dracut-kdump.sh index a2bfa05..83c1e96 100755 --- a/dracut-kdump.sh +++ b/dracut-kdump.sh @@ -9,10 +9,6 @@ exec &> /dev/console . /lib/dracut-lib.sh . /lib/kdump-lib-initramfs.sh
-if [ -f "$initdir/lib/dracut/no-emergency-shell" ]; then - rm -f -- $initdir/lib/dracut/no-emergency-shell -fi - set -o pipefail DUMP_RETVAL=0
diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh index 758420b..b9a7000 100755 --- a/dracut-module-setup.sh +++ b/dracut-module-setup.sh @@ -563,7 +563,6 @@ kdump_install_random_seed() {
install() { kdump_install_conf - >"$initdir/lib/dracut/no-emergency-shell"
if is_ssh_dump_target; then kdump_install_random_seed @@ -581,6 +580,11 @@ install() { inst_hook pre-pivot 9999 "$moddir/kdump.sh" inst "/lib/kdump/kdump-lib.sh" "/lib/kdump-lib.sh" inst "/lib/kdump/kdump-lib-initramfs.sh" "/lib/kdump-lib-initramfs.sh" + inst "$moddir/kdump-error-handler.sh" "/usr/bin/kdump-error-handler.sh" + # Replace existing emergency service + cp "$moddir/kdump-emergency.service" "$initdir/$systemdsystemunitdir/emergency.service" + # Redirect dracut-emergency to kdump error handler + ln_r "$systemdsystemunitdir/emergency.service" "$systemdsystemunitdir/dracut-emergency.service"
# Check for all the devices and if any device is iscsi, bring up iscsi # target. Ideally all this should be pushed into dracut iscsi module diff --git a/kdump-lib-initramfs.sh b/kdump-lib-initramfs.sh index 9118b64..1517712 100755 --- a/kdump-lib-initramfs.sh +++ b/kdump-lib-initramfs.sh @@ -1,6 +1,5 @@ # These variables and functions are useful in 2nd kernel
-. /lib/dracut-lib.sh . /lib/kdump-lib.sh
KDUMP_PATH="/var/crash" @@ -23,6 +22,7 @@ NEWROOT="/sysroot" get_kdump_confs() { local config_opt config_val + local user_specified_cc
while read config_opt config_val; do @@ -34,6 +34,7 @@ get_kdump_confs() ;; core_collector) [ -n "$config_val" ] && CORE_COLLECTOR="$config_val" + user_specified_cc=yes ;; sshkey) if [ -f "$config_val" ]; then @@ -55,7 +56,7 @@ get_kdump_confs() default) case $config_val in shell) - DEFAULT_ACTION="_emergency_shell kdump" + DEFAULT_ACTION="kdump_emergency_shell" ;; reboot) DEFAULT_ACTION="do_umount; reboot -f" @@ -67,12 +68,19 @@ get_kdump_confs() DEFAULT_ACTION="do_umount; poweroff -f" ;; dump_to_rootfs) - DEFAULT_ACTION="dump_fs $NEWROOT" + DEFAULT_ACTION="dump_to_rootfs" ;; esac ;; esac done < $KDUMP_CONF + + if is_ssh_dump_target || is_raw_dump_target; then + if [ -z "$user_specified_cc" ]; then + CORE_COLLECTOR="$CORE_COLLECTOR -F" + fi + fi + }
# dump_fs <mount point| device> @@ -127,6 +135,24 @@ save_vmcore_dmesg_fs() { fi }
+dump_to_rootfs() +{ + + echo "Kdump: trying to bring up rootfs device" + systemctl start dracut-initqueue + echo "Kdump: waiting for rootfs mount, will timeout after 90 seconds" + systemctl start sysroot.mount + + dump_fs $NEWROOT +} + +kdump_emergency_shell() +{ + echo "PS1="kdump:\${PWD}# "" >/etc/profile + /bin/dracut-emergency + rm -f /etc/profile +} + do_umount() { umount -Rf $NEWROOT @@ -134,7 +160,7 @@ do_umount()
do_default_action() { - wait_for_loginit + echo "Kdump: Executing default action $DEFAULT_ACTION" eval $DEFAULT_ACTION }
diff --git a/kexec-tools.spec b/kexec-tools.spec index b55a7f1..91deade 100644 --- a/kexec-tools.spec +++ b/kexec-tools.spec @@ -36,6 +36,8 @@ Source24: kdump-lib-initramfs.sh Source100: dracut-kdump.sh Source101: dracut-module-setup.sh Source102: dracut-monitor_dd_progress +Source103: dracut-kdump-error-handler.sh +Source104: dracut-kdump-emergency.service
Requires(post): systemd-units Requires(preun): systemd-units @@ -210,7 +212,8 @@ mkdir -p -m755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpba cp %{SOURCE100} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE100}} cp %{SOURCE101} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE101}} cp %{SOURCE102} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE102}} - +cp %{SOURCE103} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE103}} +cp %{SOURCE104} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE104}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE100}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE101}}
This patch introduce a new kdump-capture.service which is used to run kdump.sh.
kdump-capture.service has OnFailure=emergency.target and OnFailureIsolate=yes set. When kdump.sh fails, the kdump emergency service will be triggered and enter the error handling path.
In 2nd kernel, the default target for systemd is initrd.target, so we put kdump-capture.service in initrd.target.wants/ and by that, system will start kdump-capture as part of the boot process.
kdump.sh used to run in dracut-pre-pivot hook. Now kdump-capture.service is placed after dracut-pre-pivot.service and other dependencies are all copied from dracut-pre-pivot.service. So the start point of kdump.sh will be almost the same as it used to be.
Signed-off-by: WANG Chao chaowang@redhat.com --- dracut-kdump-capture.service | 30 ++++++++++++++++++++++++++++++ dracut-kdump.sh | 5 ++--- dracut-module-setup.sh | 4 +++- kexec-tools.spec | 2 ++ 4 files changed, 37 insertions(+), 4 deletions(-) create mode 100644 dracut-kdump-capture.service
diff --git a/dracut-kdump-capture.service b/dracut-kdump-capture.service new file mode 100644 index 0000000..57139c9 --- /dev/null +++ b/dracut-kdump-capture.service @@ -0,0 +1,30 @@ +# This file is part of systemd. +# +# systemd is free software; you can redistribute it and/or modify it +# under the terms of the GNU Lesser General Public License as published by +# the Free Software Foundation; either version 2.1 of the License, or +# (at your option) any later version. + +[Unit] +Description=Kdump Vmcore Save Service +After=initrd.target initrd-parse-etc.service sysroot.mount +After=dracut-initqueue.service dracut-pre-mount.service dracut-mount.service dracut-pre-pivot.service +Before=initrd-cleanup.service +ConditionPathExists=/etc/initrd-release +OnFailure=emergency.target +OnFailureIsolate=yes + +[Service] +Environment=DRACUT_SYSTEMD=1 +Environment=NEWROOT=/sysroot +Type=oneshot +ExecStart=/bin/kdump.sh +StandardInput=null +StandardOutput=syslog +StandardError=syslog+console +KillMode=process +RemainAfterExit=yes + +# Bash ignores SIGTERM, so we send SIGHUP instead, to ensure that bash +# terminates cleanly. +KillSignal=SIGHUP diff --git a/dracut-kdump.sh b/dracut-kdump.sh index 83c1e96..600e84e 100755 --- a/dracut-kdump.sh +++ b/dracut-kdump.sh @@ -179,8 +179,7 @@ fi get_host_ip if [ $? -ne 0 ]; then echo "kdump: get_host_ip exited with non-zero status!" - do_default_action - do_final_action + exit 1 fi
if [ -z "$DUMP_INSTRUCTION" ]; then @@ -202,7 +201,7 @@ if [ $? -ne 0 ]; then fi
if [ $DUMP_RETVAL -ne 0 ]; then - do_default_action + exit 1 fi
do_final_action diff --git a/dracut-module-setup.sh b/dracut-module-setup.sh index b9a7000..fe51a02 100755 --- a/dracut-module-setup.sh +++ b/dracut-module-setup.sh @@ -577,9 +577,11 @@ install() { inst "/bin/cut" "/bin/cut" inst "/sbin/makedumpfile" "/sbin/makedumpfile" inst "/sbin/vmcore-dmesg" "/sbin/vmcore-dmesg" - inst_hook pre-pivot 9999 "$moddir/kdump.sh" inst "/lib/kdump/kdump-lib.sh" "/lib/kdump-lib.sh" inst "/lib/kdump/kdump-lib-initramfs.sh" "/lib/kdump-lib-initramfs.sh" + inst "$moddir/kdump.sh" "/usr/bin/kdump.sh" + inst "$moddir/kdump-capture.service" "$systemdsystemunitdir/kdump-capture.service" + ln_r "$systemdsystemunitdir/kdump-capture.service" "$systemdsystemunitdir/initrd.target.wants/kdump-capture.service" inst "$moddir/kdump-error-handler.sh" "/usr/bin/kdump-error-handler.sh" # Replace existing emergency service cp "$moddir/kdump-emergency.service" "$initdir/$systemdsystemunitdir/emergency.service" diff --git a/kexec-tools.spec b/kexec-tools.spec index 91deade..1d94e3d 100644 --- a/kexec-tools.spec +++ b/kexec-tools.spec @@ -38,6 +38,7 @@ Source101: dracut-module-setup.sh Source102: dracut-monitor_dd_progress Source103: dracut-kdump-error-handler.sh Source104: dracut-kdump-emergency.service +Source105: dracut-kdump-capture.service
Requires(post): systemd-units Requires(preun): systemd-units @@ -214,6 +215,7 @@ cp %{SOURCE101} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpb cp %{SOURCE102} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE102}} cp %{SOURCE103} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE103}} cp %{SOURCE104} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE104}} +cp %{SOURCE105} $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE105}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE100}} chmod 755 $RPM_BUILD_ROOT/etc/kdump-adv-conf/kdump_dracut_modules/99kdumpbase/%{remove_dracut_prefix %{SOURCE101}}
On Thu, Jul 31, 2014 at 02:30:09PM +0800, WANG Chao wrote:
Now upon failure kdump script might not be called at all and it might not be able to execute default action. It results in a hang.
Because we disable emergency shell and rely on kdump.sh being invoked through dracut-pre-pivot hook. But it might happen that we never call into dracut-pre-pivot hook because certain systemd targets could not reach due to failure in their dependencies. In those cases error handling code does not run and system hangs. For example:
sysroot-var-crash.mount --> initrd-root-fs.target --> initrd.target \ --> dracut-pre-pivot.service --> kdump.sh
If /var/crash mount fails, local-fs.target will not be reached. And then sysinit.target will not be reached, kdump-pre-pivot.service wouldn't run. Finally kdump.sh wouldn't run.
Hey chao,
The description and call graph you have drawn are not matching. You mention that local-fs.target will not be reached but there is no local-fs.target in the graph.
You mention sysinit.target will not be reached, but there is no sysinit.target in the graph.
You mention kdump-pre-pivot.service will not run, but there isn o kdump-pre-pivot.service in the graph.
I think this description/call graph requires some fixing.
Thanks Vivek
On Thu, Jul 31, 2014 at 02:30:09PM +0800, WANG Chao wrote:
[..]
--- /dev/null +++ b/dracut-kdump-error-handler.sh @@ -0,0 +1,18 @@ +#!/bin/sh
+. /lib/kdump-lib-initramfs.sh
+set -o pipefail +export PATH=$PATH:$KDUMP_SCRIPT_DIR
+# We only allow to enter kdump error handler once. +# If error happens in error handling path and we simply reboot. +if [ -f /kdump-error-handler ]; then
- do_final_action
Why are we rebooting here. Why not simply return and exit and other instance of error handler will face error and reboot system?
+else
+fi
how about calling this file as kdump-error-handler-running. So that we nobody confuses it with actual error handler.
Thanks Vivek
On 07/31/14 at 08:58am, Vivek Goyal wrote:
On Thu, Jul 31, 2014 at 02:30:09PM +0800, WANG Chao wrote:
[..]
I just realize this doesn't work. Because dracut-initqueue.sh will call "systemctl start dracut-emergency" directly, not via "OnFailure=dracut-emergency". So this will be blocked:
dracut-initqueue (running) --> call dracut-emergency: --> dracut-emergency (running) --> call dracut-initqueue: --> blocking and waiting for the original instance to exit.
Only dracut-initqueue has such issue, because its code is written as so.
I'm thinking of introducing a wrapper emergency service. This emegency service will replace both the systemd and dracut emergency. And this service does nothing but to isolate to real kdump error handler service:
dracut-initqueue (running) --> call dracut-emergency: --> dracut-emergency isolate to kdump-error-handler.service --> dracut-emergency and dracut-initqueue will both be stopped and kdump-error-handler.service will run kdump-error-handler.sh
In a normal failure case, this still works: foo.service fails --> trigger emergency.service --> emergency.service isolates to kdump-error-handler.service --> kdump-error-handler.service will run kdump-error-handler.sh
--- /dev/null +++ b/dracut-kdump-error-handler.sh @@ -0,0 +1,18 @@ +#!/bin/sh
+. /lib/kdump-lib-initramfs.sh
+set -o pipefail +export PATH=$PATH:$KDUMP_SCRIPT_DIR
+# We only allow to enter kdump error handler once. +# If error happens in error handling path and we simply reboot. +if [ -f /kdump-error-handler ]; then
- do_final_action
Why are we rebooting here. Why not simply return and exit and other instance of error handler will face error and reboot system?
There will be only one instance of a service allowed running. If we exit from it, systemd would continue to boot for default.target (initrd.target). Because kdump.sh runs before initrd.target, kdump.sh will be run. And it's totally wrong because we've already entered kdump error handler.
"reboot" when we finish error handling makes sense, because:
1. We've already done error handling and it's nothing left for us to do. 2. Exit from error handling path will cause systemd continue to boot. We don't want go any further in an error case. Who knows what would happen if there's already something unexpected (error/failure) to make the boot unstable.
+else
+fi
how about calling this file as kdump-error-handler-running. So that we nobody confuses it with actual error handler.
I'm OK with it.
Thanks WANG Chao
On 07/31/14 at 08:52am, Vivek Goyal wrote:
On Thu, Jul 31, 2014 at 02:30:09PM +0800, WANG Chao wrote:
Now upon failure kdump script might not be called at all and it might not be able to execute default action. It results in a hang.
Because we disable emergency shell and rely on kdump.sh being invoked through dracut-pre-pivot hook. But it might happen that we never call into dracut-pre-pivot hook because certain systemd targets could not reach due to failure in their dependencies. In those cases error handling code does not run and system hangs. For example:
sysroot-var-crash.mount --> initrd-root-fs.target --> initrd.target \ --> dracut-pre-pivot.service --> kdump.sh
If /var/crash mount fails, local-fs.target will not be reached. And then sysinit.target will not be reached, kdump-pre-pivot.service wouldn't run. Finally kdump.sh wouldn't run.
Hey chao,
The description and call graph you have drawn are not matching. You mention that local-fs.target will not be reached but there is no local-fs.target in the graph.
You mention sysinit.target will not be reached, but there is no sysinit.target in the graph.
You mention kdump-pre-pivot.service will not run, but there isn o kdump-pre-pivot.service in the graph.
I think this description/call graph requires some fixing.
Yes. I messed up. In fact the graph is correct, because after "x-initrd.mount", local-fs.target becomes initrd-root-fs.target for fstab mount entry.
On 08/01/14 at 12:37am, WANG Chao wrote: [..]
--- /dev/null +++ b/dracut-kdump-error-handler.sh @@ -0,0 +1,18 @@ +#!/bin/sh
+. /lib/kdump-lib-initramfs.sh
+set -o pipefail +export PATH=$PATH:$KDUMP_SCRIPT_DIR
+# We only allow to enter kdump error handler once. +# If error happens in error handling path and we simply reboot. +if [ -f /kdump-error-handler ]; then
- do_final_action
In fact, this checking is useless. because systemd doesn't allow us to isolate to kdump-error-handler if we're already in kdump-error-handler.
IOW, we will always have one instance of kdump-error-handler running in isolation mode,
So we don't have to worry about entering it again because we can't be interrupt by another instance, and after we finish, we should reboot in any case.
Thanks WANG Chao
On Fri, Aug 01, 2014 at 01:20:15AM +0800, WANG Chao wrote:
On 08/01/14 at 12:37am, WANG Chao wrote: [..]
--- /dev/null +++ b/dracut-kdump-error-handler.sh @@ -0,0 +1,18 @@ +#!/bin/sh
+. /lib/kdump-lib-initramfs.sh
+set -o pipefail +export PATH=$PATH:$KDUMP_SCRIPT_DIR
+# We only allow to enter kdump error handler once. +# If error happens in error handling path and we simply reboot. +if [ -f /kdump-error-handler ]; then
- do_final_action
In fact, this checking is useless. because systemd doesn't allow us to isolate to kdump-error-handler if we're already in kdump-error-handler.
IOW, we will always have one instance of kdump-error-handler running in isolation mode,
So we don't have to worry about entering it again because we can't be interrupt by another instance, and after we finish, we should reboot in any case.
Ok, that's good. If systemd ensures that one can not enter another instance of error-handler, that will make our life little simple.
Thanks Vivek
-
Vivek Goyal -
WANG Chao