Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755736Ab1BORb3 (ORCPT ); Tue, 15 Feb 2011 12:31:29 -0500 Received: from mail-yw0-f46.google.com ([209.85.213.46]:59151 "EHLO mail-yw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752997Ab1BORb0 (ORCPT ); Tue, 15 Feb 2011 12:31:26 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; b=mDzkzHY06dadpOk7LqxvRsYT0AGYe0+9wF0C1aCbNvBAq1z6PCno6Dt6B3Nu9HdXRr LZBlLTPhJcqT0ztm2prWA9/SoZlqw/opE4y1JhT8aVwKFrWWaoVGfNXO2Ygx3eb7TsS6 dPBDRMq8OK/hlHqDtRypA5UvHCkD+LR38OIEY= Message-ID: <4D5AB86A.9030009@gmail.com> Date: Tue, 15 Feb 2011 20:31:22 +0300 From: Cyrill Gorcunov User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.13) Gecko/20101208 Thunderbird/3.1.7 MIME-Version: 1.0 To: Tejun Heo CC: linux-kernel@vger.kernel.org, x86@kernel.org, yinghai@kernel.org, brgerst@gmail.com, shaohui.zheng@intel.com, rientjes@google.com, mingo@elte.hu, hpa@linux.intel.com Subject: Re: [PATCH 10/26] x86-64, NUMA: Move apicid to numa mapping initialization from amd_scan_nodes() to amd_numa_init() References: <1297530663-26234-1-git-send-email-tj@kernel.org> <1297530663-26234-11-git-send-email-tj@kernel.org> <4D59B3CE.7010408@gmail.com> <20110215093631.GG3160@htj.dyndns.org> In-Reply-To: <20110215093631.GG3160@htj.dyndns.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2946 Lines: 79 On 02/15/2011 12:36 PM, Tejun Heo wrote: ... >> >> Hi Tejun, while you at it, it seems apicid_base conditional assignment is >> redundant here (boot_cpu_physical_apicid is unsigned int) so we might have >> something like >> >> apicid_start = boot_cpu_physical_apicid; >> apicid_end = apicid_start + cores; >> >> for_each_node_mask(i, cpu_nodes_parsed) { >> for (j = apicid_start; j< apicid_end; j++) >> set_apicid_to_node((i<< bits) + j, i); >> } > > Right, I think the intention there was > > if (boot_cpu_physical_apicid == -1U) > > because that's the initial value and we don't really want to index the > apicid nid table with -1U. Care to send a patch? I'm gonna have to > rebase anyway and can put the patch at the front. > > Thanks. > Hi Tejun again :) I've looked some more and if I'm not missing something (Yinghai?) the code is broken in another way. We might have AMD system with corrupted MADT table so boot_cpu_physical_apicid remains =-1U and then we better BUG_ON instead of possible access of out-of-range __apicid_to_node array. If MADT is parsed successfully boot_cpu_physical_apicid will have correct value. So I think we rather should add something like the patch below. Again better Yinghai check it first so I would not _miss_ the point that such situation is impossible at all. (And if I'm right we need to check for set_apicid_to_node(apicid, ) never exceed MAX_LOCAL_APIC as well. Yinghai am I missing something? -- Cyrill --- x86, numa: amd -- Check for screwed MADT table In case if MADT table is corrupted we might end up with boot_cpu_physical_apicid = -1U, corebits > 0 and get out of __apicid_to_node array bound access. Check for boot_cpu_physical_apicid being not default value. Signed-off-by: Cyrill Gorcunov --- arch/x86/mm/amdtopology_64.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) Index: linux-2.6.git/arch/x86/mm/amdtopology_64.c ===================================================================== --- linux-2.6.git.orig/arch/x86/mm/amdtopology_64.c +++ linux-2.6.git/arch/x86/mm/amdtopology_64.c @@ -271,9 +271,14 @@ int __init amd_scan_nodes(void) bits = boot_cpu_data.x86_coreid_bits; cores = (1< 0) { + if (boot_cpu_physical_apicid == -1U || ) { + pr_err("BAD APIC ID: %02x, NUMA node scaning canceled\n", + boot_cpu_physical_apicid); + return -1; + } else if (boot_cpu_physical_apicid > 0) { pr_info("BSP APIC ID: %02x\n", boot_cpu_physical_apicid); apicid_base = boot_cpu_physical_apicid; } -- 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/