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Commit f5154a98 authored by Hugh Dickins's avatar Hugh Dickins Committed by Linus Torvalds
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[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: default avatarHugh Dickins <hugh@veritas.com>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 9149ccfa

mm/fremap.c

+3 −0
Original line number Original line Diff line number Diff line
@@ -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;

	size = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;

	if (!page->mapping || page->index >= size)

	if (!page->mapping || page->index >= size)

		goto err_unlock;

		goto err_unlock;

	err = -ENOMEM;

	if (page_mapcount(page) > INT_MAX/2)

		goto err_unlock;





	zap_pte(mm, vma, addr, pte);

	zap_pte(mm, vma, addr, pte);