diff --git a/kernel/src/vm/vmar/vmar_impls/access_remote.rs b/kernel/src/vm/vmar/vmar_impls/access_remote.rs
index 2a5a4cfe2..97bc70c05 100644
--- a/kernel/src/vm/vmar/vmar_impls/access_remote.rs
+++ b/kernel/src/vm/vmar/vmar_impls/access_remote.rs
@@ -2,9 +2,7 @@
 
 use align_ext::AlignExt;
 use ostd::{
-    mm::{
-        HasSize, PAGE_SIZE, PageFlags, UFrame, io_util::HasVmReaderWriter, vm_space::VmQueriedItem,
-    },
+    mm::{PAGE_SIZE, PageFlags, UFrame, io_util::HasVmReaderWriter, vm_space::VmQueriedItem},
     task::disable_preempt,
 };
 
@@ -76,14 +74,11 @@ impl Vmar {
     ) -> core::result::Result<usize, (Error, usize)> {
         let mut remain = len;
         let write = |frame: UFrame, skip_offset: usize| {
-            let frame_size = frame.size();
-            let mut writer = frame.writer().to_fallible();
+            let mut writer = frame.writer();
             writer.skip(skip_offset);
-            let to_write = remain.min(frame_size - skip_offset);
-            let res = writer.fill_zeros(to_write);
-            let (Ok(n) | Err((_, n))) = &res;
-            remain -= *n;
-            res
+            let res = writer.fill_zeros(remain);
+            remain -= res;
+            Ok(res)
         };
 
         self.access_remote(vaddr, len, PageFlags::W, write)
diff --git a/kernel/src/vm/vmar/vmar_impls/mod.rs b/kernel/src/vm/vmar/vmar_impls/mod.rs
index a0e348458..9759593de 100644
--- a/kernel/src/vm/vmar/vmar_impls/mod.rs
+++ b/kernel/src/vm/vmar/vmar_impls/mod.rs
@@ -157,17 +157,13 @@ impl VmarInner {
             return Ok(());
         };
 
-        let rlimt_as = process
+        let rlimit_as = process
             .resource_limits()
             .get_rlimit(ResourceType::RLIMIT_AS)
             .get_cur();
 
-        let new_total_vm = self
-            .total_vm
-            .checked_add(expand_size)
-            .ok_or(Errno::ENOMEM)?;
-        if new_total_vm > rlimt_as as usize {
-            return_errno_with_message!(Errno::ENOMEM, "address space limit overflow");
+        if rlimit_as.saturating_sub(self.total_vm as u64) < expand_size as u64 {
+            return_errno_with_message!(Errno::ENOMEM, "the address space size limit is reached");
         }
         Ok(())
     }