From: Matthias Schiffer <mschiffer@universe-factory.net>
Date: Thu, 13 Jul 2017 00:19:32 +0200
Subject: base-files: upgrade: don't loop forever trying to kill processes

When processes don't die on SIGKILL (usually because of kernel bugs), it's
better to give up instead of looping forever.

upgraded will trigger a reboot in this case (and if this fails, a hardware
watchdog will eventually time out and reset the system, if present).

Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>

diff --git a/package/base-files/files/lib/upgrade/stage2 b/package/base-files/files/lib/upgrade/stage2
index bdbb8926643287f48a4ae62c5d1d4b4a29130859..097ad63adfecdd70019acaa5b652d2056e774c3f 100755
--- a/package/base-files/files/lib/upgrade/stage2
+++ b/package/base-files/files/lib/upgrade/stage2
@@ -87,6 +87,8 @@ switch_to_ramfs() {
 }
 
 kill_remaining() { # [ <signal> [ <loop> ] ]
+	local loop_limit=10
+
 	local sig="${1:-TERM}"
 	local loop="${2:-0}"
 	local run=true
@@ -117,8 +119,15 @@ kill_remaining() { # [ <signal> [ <loop> ] ]
 
 			[ $loop -eq 1 ] && run=true
 		done
+
+		let loop_limit--
+		[ $loop_limit -eq 0 ] && {
+			echo
+			echo "Failed to kill all processes."
+			exit 1
+		}
 	done
-	echo ""
+	echo
 }