diff --git a/zluda/src/impl/function.rs b/zluda/src/impl/function.rs
index bcb7bd6..4f2006c 100644
--- a/zluda/src/impl/function.rs
+++ b/zluda/src/impl/function.rs
@@ -153,6 +153,7 @@ pub fn launch_kernel(
                 &mut [],
             )?;
         }
+        cmd_list.close()?;
         stream.queue.execute_and_synchronize(cmd_list)?;
         Ok(())
     })?
diff --git a/zluda/src/impl/memory.rs b/zluda/src/impl/memory.rs
index 2a6236f..238d68e 100644
--- a/zluda/src/impl/memory.rs
+++ b/zluda/src/impl/memory.rs
@@ -14,6 +14,7 @@ pub fn copy_v2(dst: *mut c_void, src: *const c_void, bytesize: usize) -> Result<
     GlobalState::lock_stream(stream::CU_STREAM_LEGACY, |stream| {
         let cmd_list = stream.command_list()?;
         unsafe { cmd_list.append_memory_copy_raw(dst, src, bytesize, None, &mut [])? };
+        cmd_list.close()?;
         stream.queue.execute_and_synchronize(cmd_list)?;
         Ok::<_, CUresult>(())
     })?
@@ -40,6 +41,7 @@ pub(crate) fn set_d32_v2(dst: *mut c_void, mut ui: u32, n: usize) -> Result<(),
                 &mut [],
             )
         }?;
+        cmd_list.close()?;
         stream.queue.execute_and_synchronize(cmd_list)?;
         Ok::<_, CUresult>(())
     })?
@@ -58,6 +60,7 @@ pub(crate) fn set_d8_v2(dst: *mut c_void, mut uc: u8, n: usize) -> Result<(), CU
                 &mut [],
             )
         }?;
+        cmd_list.close()?;
         stream.queue.execute_and_synchronize(cmd_list)?;
         Ok::<_, CUresult>(())
     })?
diff --git a/zluda/src/impl/os_unix.rs b/zluda/src/impl/os_unix.rs
index dfbf305..bf3abcf 100644
--- a/zluda/src/impl/os_unix.rs
+++ b/zluda/src/impl/os_unix.rs
@@ -2,7 +2,7 @@ use std::ffi::c_void;
 use std::ptr;
 
 pub unsafe fn heap_create() -> *mut c_void {
-    ptr::null_mut()
+    usize::MAX as *mut _
 }
 
 pub unsafe fn heap_alloc(heap: *mut c_void, bytes: usize) -> *mut c_void {