do_wp_page can reach the _end callout without passing the _begin
callout. This prevents making the _end unles the _begin has also
been made.
Index: mmu_notifiers-cl-v5/mm/memory.c
===================================================================
--- mmu_notifiers-cl-v5.orig/mm/memory.c 2008-02-01 04:44:03.000000000 -0600
+++ mmu_notifiers-cl-v5/mm/memory.c 2008-02-01 04:46:18.000000000 -0600
@@ -1564,7 +1564,7 @@ static int do_wp_page(struct mm_struct *
{
struct page *old_page, *new_page;
pte_t entry;
- int reuse = 0, ret = 0;
+ int reuse = 0, ret = 0, invalidate_started = 0;
int page_mkwrite = 0;
struct page *dirty_page = NULL;
@@ -1649,6 +1649,8 @@ gotten:
mmu_notifier(invalidate_range_begin, mm, address,
address + PAGE_SIZE, 0);
+ invalidate_started = 1;
+
/*
* Re-check the pte - we dropped the lock
*/
@@ -1687,7 +1689,8 @@ gotten:
page_cache_release(old_page);
unlock:
pte_unmap_unlock(page_table, ptl);
- mmu_notifier(invalidate_range_end, mm,
+ if (invalidate_started)
+ mmu_notifier(invalidate_range_end, mm,
address, address + PAGE_SIZE, 0);
if (dirty_page) {
if (vma->vm_file)
--
