diff --git a/mkosi/mkosi.extra/usr/lib/modules-load.d/mdadm-workaround.conf b/mkosi/mkosi.extra/usr/lib/modules-load.d/mdadm-workaround.conf
new file mode 100644
index 00000000000..320f9436d37
--- /dev/null
+++ b/mkosi/mkosi.extra/usr/lib/modules-load.d/mdadm-workaround.conf
@@ -0,0 +1,10 @@
+# This is a workaround for the issue observed with mdadm-4.5 + linux-6.18.
+# ===
+# + mdadm --create /dev/md/mdmirror ...
+# mdadm: size set to 64512K
+# mdadm: Can't open /sys/module/md_mod/parameters/legacy_async_del_gendisk
+# mdadm: init md module parameters fail
+# ===
+# See also https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1125390
+# Fixed by https://github.com/md-raid-utilities/mdadm/pull/228
+md_mod