From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755457Ab3ADA4H (ORCPT ); Thu, 3 Jan 2013 19:56:07 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:26720 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754386Ab3ADAtc (ORCPT ); Thu, 3 Jan 2013 19:49:32 -0500 From: Yinghai Lu To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" Cc: "Eric W. Biederman" , Andrew Morton , Borislav Petkov , Jan Kiszka , Jason Wessel , linux-kernel@vger.kernel.org, Yinghai Lu Subject: [PATCH v7u1 01/31] x86, mm: Fix page table early allocation offset checking Date: Thu, 3 Jan 2013 16:48:21 -0800 Message-Id: <1357260531-11115-2-git-send-email-yinghai@kernel.org> X-Mailer: git-send-email 1.7.10.4 In-Reply-To: <1357260531-11115-1-git-send-email-yinghai@kernel.org> References: <1357260531-11115-1-git-send-email-yinghai@kernel.org> X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org During debugging loading kernel above 4G, found one page if is not used in BRK with early page allocation. pgt_buf_top is address that can not be used, so should check if that new end is above that top, otherwise last page will not be used. Fix that checking and also add print out for every allocation from BRK. Signed-off-by: Yinghai Lu --- arch/x86/mm/init.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/init.c b/arch/x86/mm/init.c index 6f85de8..c4293cf 100644 --- a/arch/x86/mm/init.c +++ b/arch/x86/mm/init.c @@ -47,7 +47,7 @@ __ref void *alloc_low_pages(unsigned int num) __GFP_ZERO, order); } - if ((pgt_buf_end + num) >= pgt_buf_top) { + if ((pgt_buf_end + num) > pgt_buf_top) { unsigned long ret; if (min_pfn_mapped >= max_pfn_mapped) panic("alloc_low_page: ran out of memory"); @@ -61,6 +61,8 @@ __ref void *alloc_low_pages(unsigned int num) } else { pfn = pgt_buf_end; pgt_buf_end += num; + printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n", + pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1); } for (i = 0; i < num; i++) { -- 1.7.10.4