From 0bf598d863e3c741d47e3178d645f04c9d6c186c Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Wed, 11 Sep 2013 14:22:16 -0700 Subject: [PATCH] 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 Reported-by: Dan Carpenter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/mempolicy.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 9d778637b08..04729647f35 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -1196,12 +1196,14 @@ static struct page *new_vma_page(struct page *page, unsigned long private, int * 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 -- 2.41.0