add panic init script

board/common/overlay/etc/init.d/base

@@ -6,6 +6,8 @@ board_name=$(cat /etc/board)
 
 test -n "$os_debug" || source /etc/init.d/conf
 
+source /etc/init.d/panic
+
 msg_begin() {
     echo -n " * $1: "
 }
@@ -22,8 +24,3 @@ msg_background() {
     test -n "$1" && echo $1 || echo "pending"
 }
 
-panic_action() {
-    logger -t panic -s "rebooting"
-    /sbin/reboot
-}
-

board/common/overlay/etc/init.d/panic

@@ -0,0 +1,28 @@
+#!/bin/bash
+
+_PANIC_COUNTER_FILE="/var/lib/panic_counter"
+_PANIC_REBOOT_DELAY_FACTOR=10
+_PANIC_REBOOT_DELAY_MAX=3600  # reboot at least once an hour in case of panic
+
+
+panic_action() {
+    # read counter from file
+    panic_counter=$(cat ${_PANIC_COUNTER_FILE} 2>/dev/null || echo 0)
+    
+    # write increased counter back to file
+    echo $((panic_counter + 1)) > ${_PANIC_COUNTER_FILE}
+    
+    delay=$((_PANIC_REBOOT_DELAY_FACTOR * panic_counter))
+    if [ "${delay}" -gt "${_PANIC_REBOOT_DELAY_MAX}" ]; then
+        delay=${_PANIC_REBOOT_DELAY_MAX}
+    fi
+    
+    if [ "${delay}" -gt 0 ]; then
+        logger -t panic -s "rebooting in ${delay} seconds (caused by $1)"
+        sleep ${delay}
+    fi
+
+    logger -t panic -s "rebooting (caused by $1)"
+    /sbin/reboot
+}
+

board/common/overlay/sbin/reboot

@@ -1,7 +1,15 @@
 #!/bin/bash
 
+# carry on with the script in case of error
 set +e
+
+# write buffers to disk
 /bin/sync
-(sleep 10 && /usr/bin/killall -STOP watchdog) &
+
+# allow the shutdown script 20 seconds to shut down,
+# after which we stop feeding the watchdog
+(sleep 20 && /usr/bin/killall -STOP watchdog) &
+
+# actual reboot command
 /bin/busybox reboot