[libos] Return error instead of overflow panic in vm

src/libos/src/vm/vm_manager.rs

@@ -74,14 +74,14 @@ impl VMManager {
         match addr {
             VMMapAddr::Any => {}
             VMMapAddr::Hint(addr) => {
-                let target_range = VMRange::new(addr, addr + size)?;
+                let target_range = VMRange::new_with_size(addr, size)?;
                 let ret = self.mmap_with_addr(target_range, options);
                 if ret.is_ok() {
                     return ret;
                 }
             }
             VMMapAddr::Need(addr) | VMMapAddr::Force(addr) => {
-                let target_range = VMRange::new(addr, addr + size)?;
+                let target_range = VMRange::new_with_size(addr, size)?;
                 return self.mmap_with_addr(target_range, options);
             }
         }
@@ -237,7 +237,7 @@ impl VMManager {
             }
             align_up(size, PAGE_SIZE)
         };
-        let munmap_range = { VMRange::new(addr, addr + size) }?;
+        let munmap_range = { VMRange::new_with_size(addr, size) }?;
         let chunk = {
             let current = current!();
             let process_mem_chunks = current.vm().mem_chunks().read().unwrap();

src/libos/src/vm/vm_range.rs

@@ -18,7 +18,10 @@ impl VMRange {
     }
 
     pub fn new_with_size(start: usize, size: usize) -> Result<VMRange> {
-        Self::new(start, start + size)
+        let end = start
+            .checked_add(size)
+            .ok_or_else(|| errno!(EINVAL, "end address overflow"))?;
+        Self::new(start, end)
     }
 
     pub fn new_empty(start: usize) -> Result<VMRange> {