diff --git a/lib/emscripten/src/syscalls/mod.rs b/lib/emscripten/src/syscalls/mod.rs
index 16f9c4df4..de02b998d 100644
--- a/lib/emscripten/src/syscalls/mod.rs
+++ b/lib/emscripten/src/syscalls/mod.rs
@@ -266,7 +266,7 @@ pub fn ___syscall140(ctx: &mut Ctx, _which: i32, mut varargs: VarArgs) -> i32 {
     let ret = unsafe { lseek(fd, offset, whence) as i32 };
     #[allow(clippy::cast_ptr_alignment)]
     let result_ptr = emscripten_memory_pointer!(ctx.memory(0), result_ptr_value) as *mut i32;
-    assert_eq!(4, mem::align_of_val(&result_ptr));
+    assert_eq!(8, mem::align_of_val(&result_ptr));
     unsafe {
         *result_ptr = ret;
     }