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From: Jeff Dike <jdike@addtoit.com>
To: akpm@osdl.org
Cc: "Paolo 'Blaisorblade' Giarrusso" <blaisorblade@yahoo.it>,
	linux-kernel@vger.kernel.org,
	user-mode-linux@lists.sourceforge.net
Subject: [PATCH 3/3] UML - pte_mkread fix
Date: Tue, 20 Feb 2007 11:56:38 -0500	[thread overview]
Message-ID: <20070220165638.GA6254@ccure.user-mode-linux.org> (raw)

Fix the fact that pte_mkread set _PAGE_RW instead of _PAGE_USER (the logic is
copied from i386 in most place, so it is really as bad as you're thinking).

Thus currently page tables are more permissive than they should.

Such a change may trigger other latent bugs, so be careful with this.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Jeff Dike <jdike@addtoit.com>
--
 include/asm-um/pgtable.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Index: linux-2.6.18-mm/include/asm-um/pgtable.h
===================================================================
--- linux-2.6.18-mm.orig/include/asm-um/pgtable.h	2006-10-03 12:53:16.000000000 -0400
+++ linux-2.6.18-mm/include/asm-um/pgtable.h	2006-10-09 12:25:44.000000000 -0400
@@ -270,7 +270,7 @@ static inline pte_t pte_wrprotect(pte_t 
 
 static inline pte_t pte_mkread(pte_t pte)
 { 
-	pte_set_bits(pte, _PAGE_RW);
+	pte_set_bits(pte, _PAGE_USER);
 	return(pte_mknewprot(pte)); 
 }
 

-- 
Work email - jdike at linux dot intel dot com

                 reply	other threads:[~2007-02-20 17:05 UTC|newest]

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