From: Bernhard Walle <bwalle@suse.de>
Subject: [PATCH] Add udev rule to reload kdump
References: bnc#389658

This patch

 - implements "try-restart" in the init script
 - adds a udev rule that uses "try-restart" to reload the kdump kernel
   in case of a memory or CPU hot plug event


Signed-off-by: Bernhard Walle <bwalle@suse.de>

---
 Makefile            |    1 +
 init/kdump          |   46 ++++++++++++++++++++++++++++++++++------------
 udev/70-kdump.rules |   12 ++++++++++++
 udev/Makefile       |    9 +++++++++
 4 files changed, 56 insertions(+), 12 deletions(-)

--- a/Makefile
+++ b/Makefile
@@ -30,6 +30,7 @@ install:
 	make -C init install
 	make -C gdb install
 	make -C config install
+	make -C udev install
 
 clean:
 	make -C src clean
--- a/init/kdump
+++ b/init/kdump
@@ -1,4 +1,4 @@
-#! /bin/sh
+#!/bin/bash
 #
 #  Copyright 2005 Red Hat, Inc.
 #  Author:  Jeff Moyer <jmoyer@redhat.com>
@@ -36,6 +36,25 @@ KDUMP_IDENTIFY_KERNEL=/usr/sbin/kdump-id
 
 BOOTDIR="/boot"
 
+#
+# Checks if currently a kdump kernel is loaded.
+#
+# Returns: 0 (true) if a kdump kernel is loaded,
+#          1 (false) if the kdump kernel is not loaded and
+#          -1 (false) if the feature is not implemented (too old kernel)
+kdump_kernel_loaded()
+{
+    if [ -r /sys/kernel/kexec_crash_loaded ]; then
+	if [ "$(cat /sys/kernel/kexec_crash_loaded)" = "1" ]; then
+	    return 0
+	else
+	    return 1
+	fi
+    else
+	return -1
+    fi
+}
+
 # The default dumper
 #
 # Clean up old stuff if necessary, check the free size
@@ -303,24 +322,27 @@ case "$1" in
 	fi
 	;;
   status)
-	if [ -r /sys/kernel/kexec_crash_loaded ]; then
-	    if [ "$(cat /sys/kernel/kexec_crash_loaded)" = "1" ]; then
-		echo "kdump kernel loaded"
-	    else
-		echo "kdump kernel not loaded"
-	    fi
-	else
-	    echo "not implemented"
-	fi
+  	kdump_kernel_loaded
+	case $? in
+	     0)	    echo "kdump kernel loaded" 		;;
+	     1)     echo "kdump kernel not loaded"	;;
+	    -1)     echo "not implemented"		;;
+	esac
 	;;
   restart|reload)
 	$0 stop
 	$0 start
 	;;
-  condrestart)
+  condrestart|try-restart)
+  	if kdump_kernel_loaded ; then
+  	    $0 start
+	else
+	    rc_reset
+        fi
+	rc_status
 	;;
   *)
-	echo $"Usage: $0 {start|stop|status|restart|reload}"
+	echo $"Usage: $0 {start|stop|status|restart|reload|try-reload}"
 	exit 1
 esac
 
--- /dev/null
+++ b/udev/70-kdump.rules
@@ -0,0 +1,12 @@
+#
+# Kdump core headers needs to be regnerated if the CPUs or memory changes.
+# For this, reload kdump.
+#
+# Novell Bug #389658
+#
+
+SUBSYSTEM=="cpu", ACTION=="online", PROGRAM="/etc/init.d/kdump try-restart"
+SUBSYSTEM=="cpu", ACTION=="offline", PROGRAM="/etc/init.d/kdump try-restart"
+SUBSYSTEM=="memory", ACTION=="add", PROGRAM="/etc/init.d/kdump try-restart"
+SUBSYSTEM=="memory", ACTION=="remove", PROGRAM="/etc/init.d/kdump try-restart"
+
--- /dev/null
+++ b/udev/Makefile
@@ -0,0 +1,9 @@
+# Simple makefile to build kdump-helper
+#
+# (c) 2008, Bernhard Walle <bwalle@suse.de>, SUSE LINUX Products GmbH
+
+
+install:
+	mkdir -p $(DESTDIR)$(SYSCONFDIR)/udev/rules.d
+	install -m 0644 70-kdump.rules $(DESTDIR)$(SYSCONFDIR)/udev/rules.d
+