diff --git a/src/syscall/fs.rs b/src/syscall/fs.rs
index 63bfe87508..f1080fdd37 100644
--- a/src/syscall/fs.rs
+++ b/src/syscall/fs.rs
@@ -832,7 +832,7 @@ pub fn sys_read(fd: FileHandle, buf: UserSliceWo, token: &mut CleanLockToken) ->
             let offset = if desc.internal_flags.contains(InternalFlags::POSITIONED) {
                 desc.offset
             } else {
-                0
+                u64::MAX
             };
             Ok((
                 scheme.kreadoff(desc.number, buf, offset, desc.flags, desc.flags, token)?,
@@ -861,7 +861,7 @@ pub fn sys_write(fd: FileHandle, buf: UserSliceRo, token: &mut CleanLockToken) -
             let offset = if desc.internal_flags.contains(InternalFlags::POSITIONED) {
                 desc.offset
             } else {
-                0
+                u64::MAX
             };
             Ok((
                 scheme.kwriteoff(desc.number, buf, offset, desc.flags, desc.flags, token)?,