From mboxrd@z Thu Jan  1 00:00:00 1970
Date: Fri, 11 Aug 2006 02:15:19 -0700
Message-Id: <200608110915.k7B9FJxV023257@zach-dev.vmware.com>
Subject: [PATCH 1/9] 00mm1 remove read hazard from cow.patch
From: Zachary Amsden <zach@vmware.com>
Sender: owner-linux-mm@kvack.org
Return-Path: <owner-linux-mm@kvack.org>
To: Andrew Morton <akpm@osdl.org>, Andi Kleen <ak@suse.de>, Zachary Amsden <zach@vmware.com>, Chris Wright <chrisw@osdl.org>, Rusty Russell <rusty@rustcorp.com.au>, Jeremy Fitzhardinge <jeremy@goop.org>, Virtualization Mailing List <virtualization@lists.osdl.org>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Linux MM <linux-mm@kvack.org>, ":"@vmware.comZachary Amsden <zach@vmware.com>
List-ID: <linux-mm.kvack.org>

We don't want to read PTEs directly like this after they have been
modified, as a lazy MMU implementation of direct page tables may not
have written the updated PTE back to memory yet.

Signed-off-by: Zachary Amsden <zach@vmware.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Cc: linux-mm@kvack.org

---
 mm/memory.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)


===================================================================
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -466,7 +466,7 @@ copy_one_pte(struct mm_struct *dst_mm, s
 	 */
 	if (is_cow_mapping(vm_flags)) {
 		ptep_set_wrprotect(src_mm, addr, src_pte);
-		pte = *src_pte;
+		pte = pte_wrprotect(pte);
 	}
 
 	/*

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