From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760394AbYCCAUz (ORCPT ); Sun, 2 Mar 2008 19:20:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756371AbYCCATD (ORCPT ); Sun, 2 Mar 2008 19:19:03 -0500 Received: from ogre.sisk.pl ([217.79.144.158]:41107 "EHLO ogre.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761454AbYCCATA (ORCPT ); Sun, 2 Mar 2008 19:19:00 -0500 From: "Rafael J. Wysocki" To: Linus Torvalds Subject: [PATCH] x86: Revert commit 8be8f54bae3453588011cad06363813a5293af53 Date: Mon, 3 Mar 2008 01:17:37 +0100 User-Agent: KMail/1.9.6 (enterprise 20070904.708012) Cc: Ingo Molnar , LKML , Thomas Gleixner , Andrew Morton MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200803030117.38344.rjw@sisk.pl> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Rafael J. Wysocki Revert commit 8be8f54bae3453588011cad06363813a5293af53 Author: Thomas Gleixner Date: Sat Feb 23 20:43:21 2008 +0100 x86: CPA: avoid split of alias mappings because it clearly mishandles the case when __change_page_attr(), called from __change_page_attr_set_clr(), changes cpa->processed to 1 and cpa_process_alias(cpa) is executed right after that. This crashes my x86-64 test box early in the boot process (ref. http://bugzilla.kernel.org/show_bug.cgi?id=10140#c4). Signed-off-by: Rafael J. Wysocki Acked-by: Thomas Gleixner --- arch/x86/mm/pageattr.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) Index: linux-2.6/arch/x86/mm/pageattr.c =================================================================== --- linux-2.6.orig/arch/x86/mm/pageattr.c +++ linux-2.6/arch/x86/mm/pageattr.c @@ -26,7 +26,6 @@ struct cpa_data { pgprot_t mask_set; pgprot_t mask_clr; int numpages; - int processed; int flushtlb; unsigned long pfn; }; @@ -291,8 +290,8 @@ try_preserve_large_page(pte_t *kpte, uns */ nextpage_addr = (address + psize) & pmask; numpages = (nextpage_addr - address) >> PAGE_SHIFT; - if (numpages < cpa->processed) - cpa->processed = numpages; + if (numpages < cpa->numpages) + cpa->numpages = numpages; /* * We are safe now. Check whether the new pgprot is the same: @@ -319,7 +318,7 @@ try_preserve_large_page(pte_t *kpte, uns */ addr = address + PAGE_SIZE; pfn++; - for (i = 1; i < cpa->processed; i++, addr += PAGE_SIZE, pfn++) { + for (i = 1; i < cpa->numpages; i++, addr += PAGE_SIZE, pfn++) { pgprot_t chk_prot = static_protections(new_prot, addr, pfn); if (pgprot_val(chk_prot) != pgprot_val(new_prot)) @@ -343,7 +342,7 @@ try_preserve_large_page(pte_t *kpte, uns * that we limited the number of possible pages already to * the number of pages in the large page. */ - if (address == (nextpage_addr - psize) && cpa->processed == numpages) { + if (address == (nextpage_addr - psize) && cpa->numpages == numpages) { /* * The address is aligned and the number of pages * covers the full page. @@ -573,7 +572,7 @@ repeat: set_pte_atomic(kpte, new_pte); cpa->flushtlb = 1; } - cpa->processed = 1; + cpa->numpages = 1; return 0; } @@ -584,7 +583,7 @@ repeat: do_split = try_preserve_large_page(kpte, address, cpa); /* * When the range fits into the existing large page, - * return. cp->processed and cpa->tlbflush have been updated in + * return. cp->numpages and cpa->tlbflush have been updated in * try_large_page: */ if (do_split <= 0) @@ -663,7 +662,7 @@ static int __change_page_attr_set_clr(st * Store the remaining nr of pages for the large page * preservation check. */ - cpa->numpages = cpa->processed = numpages; + cpa->numpages = numpages; ret = __change_page_attr(cpa, checkalias); if (ret) @@ -680,9 +679,9 @@ static int __change_page_attr_set_clr(st * CPA operation. Either a large page has been * preserved or a single page update happened. */ - BUG_ON(cpa->processed > numpages); - numpages -= cpa->processed; - cpa->vaddr += cpa->processed * PAGE_SIZE; + BUG_ON(cpa->numpages > numpages); + numpages -= cpa->numpages; + cpa->vaddr += cpa->numpages * PAGE_SIZE; } return 0; }