From caf5fa955bd4de8889f388cabc4dc33bd4a5f9f1 Mon Sep 17 00:00:00 2001
From: bjorn3 <17426603+bjorn3@users.noreply.github.com>
Date: Sun, 6 Jul 2025 16:08:38 +0200
Subject: [PATCH] Fix freeing of phys_contiguous frames

Previously the deallocation would be rounded to the next power of two
preventing partial deallocation. But more importantly previously trying
to free phys_contiguous frames while another processes still borrows
them. Now this should just cause the deallocation to be delayed.
---
 src/context/memory.rs | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/context/memory.rs b/src/context/memory.rs
index 890eb5b21e..6234d67399 100644
--- a/src/context/memory.rs
+++ b/src/context/memory.rs
@@ -15,8 +15,8 @@ use crate::{
     context::arch::setup_new_utable,
     cpu_set::LogicalCpuSet,
     memory::{
-        deallocate_frame, deallocate_p2frame, get_page_info, init_frame, the_zeroed_frame,
-        AddRefError, Enomem, Frame, PageInfo, RaiiFrame, RefCount, RefKind,
+        deallocate_frame, get_page_info, init_frame, the_zeroed_frame, AddRefError, Enomem, Frame,
+        PageInfo, RaiiFrame, RefCount, RefKind,
     },
     paging::{Page, PageFlags, PageMapper, RmmA, TableKind, VirtualAddress},
     percpu::PercpuBlock,
@@ -2719,15 +2719,17 @@ impl GenericFlusher for NopFlusher {
 fn handle_free_action(base: Frame, phys_contiguous_count: Option<NonZeroUsize>) {
     if let Some(count) = phys_contiguous_count {
         for i in 0..count.get() {
-            let new_rc = get_page_info(base.next_by(i))
+            let frame = base.next_by(i);
+            let new_rc = get_page_info(frame)
                 .expect("phys_contiguous frames all need PageInfos")
                 .remove_ref();
 
-            assert_eq!(new_rc, None);
-        }
-        unsafe {
-            let order = count.get().next_power_of_two().trailing_zeros();
-            deallocate_p2frame(base, order);
+            if new_rc.is_none() {
+                // FIXME use a single deallocate_p2frame when possible
+                unsafe {
+                    deallocate_frame(frame);
+                }
+            }
         }
     } else {
         let Some(info) = get_page_info(base) else {