[PATCH] mincore: vma crossing fix

My mincore also forgot about crossing vmas.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/mm/mincore.c b/mm/mincore.c
index 9c1d0a426e95..5efe0ded69b1 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -77,8 +77,16 @@ static long do_mincore(unsigned long addr, unsigned char *vec, unsigned long pag
          * PTE array for our address.
          */
         nr = PTRS_PER_PTE - ((addr >> PAGE_SHIFT) & (PTRS_PER_PTE-1));
-        if (nr > pages)
-                nr = pages;
+
+        /*
+         * Don't overrun this vma
+         */
+        nr = min(nr, (vma->vm_end - addr) >> PAGE_SHIFT);
+
+        /*
+         * Don't return more than the caller asked for
+         */
+        nr = min(nr, pages);
 
         pgd = pgd_offset(vma->vm_mm, addr);
         if (pgd_none_or_clear_bad(pgd))