diff --git a/pkgs/os-specific/linux/mdadm/default.nix b/pkgs/os-specific/linux/mdadm/default.nix
index 14a3589aff33..e9e90b3c388b 100644
--- a/pkgs/os-specific/linux/mdadm/default.nix
+++ b/pkgs/os-specific/linux/mdadm/default.nix
@@ -9,7 +9,10 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-QWcnrh8QgOpuMJDOo23QdoJvw2kVHjarc2VXupIZb58=";
   };
 
-  patches = [ ./no-self-references.patch ];
+  patches = [
+    ./no-self-references.patch
+    ./fix-hardcoded-mapdir.patch
+  ];
 
   makeFlags = [
     "NIXOS=1" "INSTALL=install" "BINDIR=$(out)/sbin"
diff --git a/pkgs/os-specific/linux/mdadm/fix-hardcoded-mapdir.patch b/pkgs/os-specific/linux/mdadm/fix-hardcoded-mapdir.patch
new file mode 100644
index 000000000000..cf50d6012487
--- /dev/null
+++ b/pkgs/os-specific/linux/mdadm/fix-hardcoded-mapdir.patch
@@ -0,0 +1,13 @@
+diff --git a/udev.c b/udev.c
+index bc4722b0..aa2a1a24 100644
+--- a/udev.c
++++ b/udev.c
+@@ -167,7 +167,7 @@ enum udev_status udev_block(char *devnm)
+ 	int fd;
+ 	char *path = xcalloc(1, BUFSIZ);
+ 
+-	snprintf(path, BUFSIZ, "/run/mdadm/creating-%s", devnm);
++	snprintf(path, BUFSIZ, "%s/creating-%s", MAP_DIR, devnm);
+ 
+ 	fd = open(path, O_CREAT | O_RDWR, 0600);
+ 	if (!is_fd_valid(fd)) {