diff --git a/test/shell/snapshot-autoumount-dmeventd.sh b/test/shell/snapshot-autoumount-dmeventd.sh
index db4062e7c..e0596849c 100644
--- a/test/shell/snapshot-autoumount-dmeventd.sh
+++ b/test/shell/snapshot-autoumount-dmeventd.sh
@@ -32,7 +32,7 @@ mkdir "$mntdir"
 mount "$DM_DEV_DIR/mapper/$vg-snap" "$mntdir"
 mount
 cat /proc/mounts | grep "$mntdir"
-dd if=/dev/zero of="$mntdir/file$1" bs=1M count=5 oflag=direct
+not dd if=/dev/zero of="$mntdir/file$1" bs=1M count=5 oflag=direct
 
 #dmeventd only checks every 10 seconds :(
 for i in {1..10}; do