mm/mlock.c: change count_mm_mlocked_page_nr return type

On a 64-bit machine the value of "vma->vm_end - vma->vm_start" may be negative when using 32 bit ints and the "count >> PAGE_SHIFT"'s result will be wrong. So change the local variable and return value to unsigned long to fix the problem. Link: http://lkml.kernel.org/r/[email protected] Fixes: 0cf2f6f ("mm: mlock: check against vma for actual mlock() size") Signed-off-by: swkhack <[email protected]> Acked-by: Michal Hocko <[email protected]> Reviewed-by: Andrew Morton <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
heikomat · Jun 14, 2019 · 0874bb4 · 0874bb4
1 parent 7a30df4
commit 0874bb4
Showing 1 changed file with 2 additions and 2 deletions.
diff --git a/mm/mlock.c b/mm/mlock.c
@@ -636,11 +636,11 @@ static int apply_vma_lock_flags(unsigned long start, size_t len,
  * is also counted.
  * Return value: previously mlocked page counts
  */
-static int count_mm_mlocked_page_nr(struct mm_struct *mm,
+static unsigned long count_mm_mlocked_page_nr(struct mm_struct *mm,
 		unsigned long start, size_t len)
 {
 	struct vm_area_struct *vma;
-	int count = 0;
+	unsigned long count = 0;
 
 	if (mm == NULL)
 		mm = current->mm;