mbind: add BUG_ON(!vma) in new_vma_page()
new_vma_page() is called only by page migration called from do_mbind(),
where pages to be migrated are queued into a pagelist by
queue_pages_range(). queue_pages_range() confirms that a queued page
belongs to some vma, so !vma case is not supposed to be happen. This
patch adds BUG_ON() to catch this unexpected case.
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 9d77863..0472964 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1196,12 +1196,14 @@
break;
vma = vma->vm_next;
}
+ /*
+ * queue_pages_range() confirms that @page belongs to some vma,
+ * so vma shouldn't be NULL.
+ */
+ BUG_ON(!vma);
if (PageHuge(page))
return alloc_huge_page_noerr(vma, address, 1);
- /*
- * if !vma, alloc_page_vma() will use task or system default policy
- */
return alloc_page_vma(GFP_HIGHUSER_MOVABLE, vma, address);
}
#else