[PATCH 1/2] mm hugetlb x86: fix hugepage memory leak in walk_page_range()

Naoya Horiguchi
2009-12-07T08:01:43Z

Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
---
mm/pagewalk.c | 15 ++++++++++++++-
1 files changed, 14 insertions(+), 1 deletions(-)

diff --git a/mm/pagewalk.c b/mm/pagewalk.c
index d5878be..3d88824 100644
--- a/mm/pagewalk.c
+++ b/mm/pagewalk.c
@@ -1,6 +1,7 @@
#include <linux/mm.h>
#include <linux/highmem.h>
#include <linux/sched.h>
+#include <linux/hugetlb.h>

static int walk_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
struct mm_walk *walk)
@@ -107,6 +108,7 @@ int walk_page_range(unsigned long addr, unsigned long end,
pgd_t *pgd;
unsigned long next;
int err = 0;
+ struct vm_area_struct *vma;

if (addr >= end)
return err;
@@ -117,11 +119,21 @@ int walk_page_range(unsigned long addr, unsigned long end,
pgd = pgd_offset(walk->mm, addr);
do {
next = pgd_addr_end(addr, end);
+
+ /* skip hugetlb vma to avoid hugepage PMD being cleared
+ * in pmd_none_or_clear_bad(). */
+ vma = find_vma(walk->mm, addr);
+ if (is_vm_hugetlb_page(vma)) {
+ next = (vma->vm_end < next) ? vma->vm_end : next;
+ continue;
+ }
+
if (pgd_none_or_clear_bad(pgd)) {
if (walk->pte_hole)
err = walk->pte_hole(addr, next, walk);
if (err)
break;
+ pgd++;
continue;
}
if (walk->pgd_entry)
@@ -131,7 +143,8 @@ int walk_page_range(unsigned long addr, unsigned long end,
err = walk_pud_range(pgd, addr, next, walk);
if (err)
break;
- } while (pgd++, addr = next, addr != end);
+ pgd++;
+ } while (addr = next, addr != end);

return err;
}
--
1.6.0.6