diff --git a/helper/tmpdir-setup b/helper/tmpdir-setup
index 5b5e1808..384d9bec 100755
--- a/helper/tmpdir-setup
+++ b/helper/tmpdir-setup
@@ -61,12 +61,10 @@ cmd_cleanup() {
     # Support rolling upgrade: Use old code if loop device is directly mounted without a dm device in between.
     #
     if [[ $(findmnt --output SOURCE --noheadings /dev/shm/mxqd/mnt/job/$MXQ_JOBID) =~ ^/dev/loop ]]; then
-        (
-            shopt -s dotglob
-            rm -rf /dev/shm/mxqd/mnt/job/$MXQ_JOBID/*
-            umount /dev/shm/mxqd/mnt/job/$MXQ_JOBID
-            rmdir /dev/shm/mxqd/mnt/job/$MXQ_JOBID
-        ) &
+        shopt -s dotglob
+        rm -rf /dev/shm/mxqd/mnt/job/$MXQ_JOBID/*
+        umount /dev/shm/mxqd/mnt/job/$MXQ_JOBID
+        rmdir /dev/shm/mxqd/mnt/job/$MXQ_JOBID
         exit
     fi