Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932263AbaAaKFY (ORCPT ); Fri, 31 Jan 2014 05:05:24 -0500 Received: from cantor2.suse.de ([195.135.220.15]:38165 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932072AbaAaKFW (ORCPT ); Fri, 31 Jan 2014 05:05:22 -0500 Date: Fri, 31 Jan 2014 11:05:17 +0100 From: Petr Tesarik To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org Cc: Jiang Liu , Andrew Morton , Dave Hansen , linux-kernel@vger.kernel.org Subject: [PATCH] x86: fix the initialization of physnode_map Message-ID: <20140131110517.4b7e86d6@hananiah.suse.cz> Organization: SUSE Linux, s.r.o. X-Mailer: Claws Mail 3.9.2 (GTK+ 2.24.22; x86_64-suse-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With DISCONTIGMEM, the mapping between a pfn and its owning node is initialized using data provided by the BIOS or from the command line. However, the initialization may fail if the extents are not aligned to section boundary (64M). The symptom of this bug is an early boot failure in pfn_to_page(), as it tries to access NODE_DATA(__nid) using index from an unitialized element of the physnode_map[] array. While the bug is always present, it is more likely to be hit in kdump kernels on large machines, because: 1. The memory map for a kdump kernel is specified as exactmap, and exactmap is more likely to be unaligned. 2. Large reservations are more likely to span across a 64M boundary. Signed-off-by: Petr Tesarik --- arch/x86/mm/numa_32.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/mm/numa_32.c b/arch/x86/mm/numa_32.c index 0342d27..f278b04 100644 --- a/arch/x86/mm/numa_32.c +++ b/arch/x86/mm/numa_32.c @@ -46,15 +46,16 @@ EXPORT_SYMBOL(physnode_map); void memory_present(int nid, unsigned long start, unsigned long end) { - unsigned long pfn; + unsigned long sect, endsect; printk(KERN_INFO "Node: %d, start_pfn: %lx, end_pfn: %lx\n", nid, start, end); printk(KERN_DEBUG " Setting physnode_map array to node %d for pfns:\n", nid); printk(KERN_DEBUG " "); - for (pfn = start; pfn < end; pfn += PAGES_PER_SECTION) { - physnode_map[pfn / PAGES_PER_SECTION] = nid; - printk(KERN_CONT "%lx ", pfn); + endsect = (end - 1) / PAGES_PER_SECTION; + for (sect = start / PAGES_PER_SECTION; sect <= endsect; ++sect) { + physnode_map[sect] = nid; + printk(KERN_CONT "%lx ", sect * PAGES_PER_SECTION); } printk(KERN_CONT "\n"); } -- 1.8.4.5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/