Add final_action option to kdump.conf

If a crash occurs repeatedly after enabling kdump, the system goes
into a crash loop and the dump target may get filled up by vmcores.
This is likely especially with early kdump.

This patch introduces 'final_action' option to kdump.conf, in order
for users to be able to power off the system even after capturing
a vmcore successfully.

Signed-off-by: Kazuhito Hagio <k-hagio@ab.jp.nec.com>
Cc: Dave Young <dyoung@redhat.com>
Cc: Lianbo Jiang <lijiang@redhat.com>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Bhupesh Sharma <bhsharma@redhat.com>
Acked-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Kairui Song <kasong@redhat.com>

fadump-howto.txt

@@ -73,7 +73,8 @@ The control flow of fadump works as follows:
 10. Is dump capture successful (yes goto 12, no goto 11)
 11. Perform the failure action specified in /etc/kdump.conf
     (The default failure action is reboot, if unspecified)
-12. Reboot
+12. Perform the final action specified in /etc/kdump.conf
+    (The default final action is reboot, if unspecified)
 
 
 How to configure fadump:

kdump-lib-initramfs.sh

@@ -70,6 +70,19 @@ get_kdump_confs()
                     ;;
                 esac
             ;;
+            final_action)
+                case $config_val in
+                    reboot)
+                        FINAL_ACTION="systemctl reboot -f"
+                    ;;
+                    halt)
+                        FINAL_ACTION="halt"
+                    ;;
+                    poweroff)
+                        FINAL_ACTION="systemctl poweroff -f"
+                    ;;
+                esac
+            ;;
         esac
     done < $KDUMP_CONF
 

kdump.conf

@@ -105,15 +105,23 @@
 #             halt:     Halt the system.
 #             poweroff: Power down the system.
 #             shell:    Drop to a bash shell.
-#                       Exiting the shell reboots the system.
+#                       Exiting the shell reboots the system by default,
+#                       or perform "final_action".
 #             dump_to_rootfs:  Dump vmcore to rootfs from initramfs context and
-#                       reboot. Useful when non-root dump target is specified.
+#                       reboot by default or perform "final_action".
+#                       Useful when non-root dump target is specified.
 #             The default option is "reboot".
 #
 # default <reboot | halt | poweroff | shell | dump_to_rootfs>
 #           - Same as the "failure_action" directive above, but this directive
 #             is obsolete and will be removed in the future.
 #
+# final_action <reboot | halt | poweroff>
+#           - Action to perform in case dumping succeeds. Also performed
+#             when "shell" or "dump_to_rootfs" failure action finishes.
+#             Each action is same as the "failure_action" directive above.
+#             The default is "reboot".
+#
 # force_rebuild <0 | 1>
 #           - By default, kdump initrd will only be rebuilt when necessary.
 #             Specify 1 to force rebuilding kdump initrd every time when kdump

kdump.conf.5

@@ -155,9 +155,11 @@ reboot: Reboot the system (this is what most people will want, as it returns the
 to a normal state).  halt: Halt the system and lose the vmcore.  poweroff: The system
 will be powered down.  shell: Drop to a shell session inside the initramfs, from which
 you can manually perform additional recovery actions.  Exiting this shell reboots the
-system.  Note: kdump uses bash as the default shell.  dump_to_rootfs: If non-root dump
+system by default or performs "final_action".
+Note: kdump uses bash as the default shell.  dump_to_rootfs: If non-root dump
 target is specified, the failure action can be set as dump_to_rootfs.  That means when
-dumping to target fails, dump vmcore to rootfs from initramfs context and reboot.
+dumping to target fails, dump vmcore to rootfs from initramfs context and reboot
+by default or perform "final_action".
 .RE
 
 .B default <reboot | halt | poweroff | shell | dump_to_rootfs>
@@ -166,6 +168,14 @@ Same as the "failure_action" directive above, but this directive is obsolete
 and will be removed in the future.
 .RE
 
+.B final_action <reboot | halt | poweroff>
+.RS
+Action to perform in case dumping to the intended target succeeds.
+Also performed when "shell" or "dump_to_rootfs" failure action finishes.
+Each action is same as the "failure_action" directive above.
+The default is "reboot".
+.RE
+
 .B force_rebuild <0 | 1>
 .RS
 By default, kdump initrd will only be rebuilt when necessary.

kdumpctl

@@ -228,7 +228,7 @@ check_config()
 		case "$config_opt" in
 		\#* | "")
 			;;
-		raw|ext2|ext3|ext4|minix|btrfs|xfs|nfs|ssh|sshkey|path|core_collector|kdump_post|kdump_pre|extra_bins|extra_modules|failure_action|default|force_rebuild|force_no_rebuild|dracut_args|fence_kdump_args|fence_kdump_nodes)
+		raw|ext2|ext3|ext4|minix|btrfs|xfs|nfs|ssh|sshkey|path|core_collector|kdump_post|kdump_pre|extra_bins|extra_modules|failure_action|default|final_action|force_rebuild|force_no_rebuild|dracut_args|fence_kdump_args|fence_kdump_nodes)
 			# remove inline comments after the end of a directive.
 			config_val=$(strip_comments $config_val)
 			[ -z "$config_val" ] && {
@@ -248,6 +248,7 @@ check_config()
 	done < $KDUMP_CONFIG_FILE
 
 	check_failure_action_config || return 1
+	check_final_action_config || return 1
 
 	check_fence_kdump_config || return 1
 
@@ -966,6 +967,25 @@ check_failure_action_config()
 	esac
 }
 
+check_final_action_config()
+{
+	local final_action
+
+	final_action=$(awk '$1 ~ /^final_action$/ {print $2;}' $KDUMP_CONFIG_FILE)
+	if [ -z "$final_action" ]; then
+		return 0
+	else
+		case "$final_action" in
+		  reboot|halt|poweroff)
+			return 0
+		  ;;
+		  *)
+			echo $"Usage kdump.conf: final_action {reboot|halt|poweroff}"
+			return 1
+		esac
+	fi
+}
+
 start()
 {
 	check_dump_feasibility