From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935800Ab3DJN3i (ORCPT ); Wed, 10 Apr 2013 09:29:38 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1493 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752466Ab3DJN3g (ORCPT ); Wed, 10 Apr 2013 09:29:36 -0400 From: Andrea Arcangeli To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Andrew Morton , Stefan Bader , Andy Whitcroft , Mel Gorman , Borislav Petkov Subject: [PATCH] mm: pageattr: convert noop to functional fix Date: Wed, 10 Apr 2013 15:28:25 +0200 Message-Id: <1365600505-19314-1-git-send-email-aarcange@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit a8aed3e0752b4beb2e37cbed6df69faae88268da introduced some valid fix but one location that didn't trigger the bug that lead to finding those (small) problems, wasn't updated using the right variable. The wrong variable was also initialized for no good reason, that may have been the source of the confusion. Remove the noop initialization accordingly. Commit a8aed3e0752b4beb2e37cbed6df69faae88268da also erroneously removed one canon_pgprot pass meant to clear pmd bitflags not supported in hardware by older CPUs, that automatically gets corrected by this patch too by applying it to the right variable in the new location. Reported-by: Stefan Bader Signed-off-by: Andrea Arcangeli --- arch/x86/mm/pageattr.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index 091934e..7896f71 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -467,7 +467,7 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * We are safe now. Check whether the new pgprot is the same: */ old_pte = *kpte; - old_prot = new_prot = req_prot = pte_pgprot(old_pte); + old_prot = req_prot = pte_pgprot(old_pte); pgprot_val(req_prot) &= ~pgprot_val(cpa->mask_clr); pgprot_val(req_prot) |= pgprot_val(cpa->mask_set); @@ -478,12 +478,12 @@ try_preserve_large_page(pte_t *kpte, unsigned long address, * a non present pmd. The canon_pgprot will clear _PAGE_GLOBAL * for the ancient hardware that doesn't support it. */ - if (pgprot_val(new_prot) & _PAGE_PRESENT) - pgprot_val(new_prot) |= _PAGE_PSE | _PAGE_GLOBAL; + if (pgprot_val(req_prot) & _PAGE_PRESENT) + pgprot_val(req_prot) |= _PAGE_PSE | _PAGE_GLOBAL; else - pgprot_val(new_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL); + pgprot_val(req_prot) &= ~(_PAGE_PSE | _PAGE_GLOBAL); - new_prot = canon_pgprot(new_prot); + req_prot = canon_pgprot(req_prot); /* * old_pte points to the large page base address. So we need