From f5154a98a1931641f0448f6512294a15279110d7 Mon Sep 17 00:00:00 2001 From: Hugh Dickins Date: Tue, 11 Oct 2005 19:16:26 +0100 Subject: [PATCH] Don't map the same page too much Refuse to install a page into a mapping if the mapping count is already ridiculously large. You probably cannot trigger this on 32-bit architectures, but on a 64-bit setup we should protect against it. Signed-off-by: Hugh Dickins Signed-off-by: Linus Torvalds --- mm/fremap.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'mm/fremap.c') diff --git a/mm/fremap.c b/mm/fremap.c index 3235fb77c133..ab23a0673c35 100644 --- a/mm/fremap.c +++ b/mm/fremap.c @@ -89,6 +89,9 @@ int install_page(struct mm_struct *mm, struct vm_area_struct *vma, size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT; if (!page->mapping || page->index >= size) goto err_unlock; + err = -ENOMEM; + if (page_mapcount(page) > INT_MAX/2) + goto err_unlock; zap_pte(mm, vma, addr, pte); -- cgit v1.2.3-59-g8ed1b