diff --git a/pageserver/src/virtual_file/owned_buffers_io/write/zero_initialized_buffer.rs b/pageserver/src/virtual_file/owned_buffers_io/write/zero_initialized_buffer.rs
index 90b7e9182a..a48bb9767a 100644
--- a/pageserver/src/virtual_file/owned_buffers_io/write/zero_initialized_buffer.rs
+++ b/pageserver/src/virtual_file/owned_buffers_io/write/zero_initialized_buffer.rs
@@ -54,6 +54,10 @@ impl<const N: usize> Buf<N> {
     }
 }
 
+/// SAFETY:
+///
+/// The [`Self::allocation`] is stable becauses boxes are stable.
+///
 unsafe impl<const N: usize> tokio_epoll_uring::IoBuf for Buf<N> {
     fn stable_ptr(&self) -> *const u8 {
         self.allocation.as_ptr()