Index: sys/mips/mips/machdep.c
===================================================================
--- sys/mips/mips/machdep.c
+++ sys/mips/mips/machdep.c
@@ -383,7 +383,16 @@
 void
 mips_postboot_fixup(void)
 {
-	static char fake_preload[256];
+	/*
+	 * Ensure the buffer is properly aligned to hold module metadata structures.
+	 * When building the kernel with gcc+bfd fake_preload was always
+	 * sufficiently aligned. However, when building with clang the compiler is
+	 * less conservative and will only align it to 4 bytes which is not enough
+	 * on a MIPS64 system which will use `sd` to store to this buffer.
+	 *
+	 * TODO: Once we depend on C11 we can use _Alignas(u_long) instead.
+	 */
+	static char fake_preload[256] __aligned(_Alignof(u_long));
 	caddr_t preload_ptr = (caddr_t)&fake_preload[0];
 	size_t size = 0;