From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752177AbeEPWrB (ORCPT ); Wed, 16 May 2018 18:47:01 -0400 Received: from mx2.suse.de ([195.135.220.15]:57524 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751880AbeEPWrA (ORCPT ); Wed, 16 May 2018 18:47:00 -0400 Date: Thu, 17 May 2018 00:46:41 +0200 From: Borislav Petkov To: Johannes Hirte , "Ghannam, Yazen" Cc: "linux-edac@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "tony.luck@intel.com" , "x86@kernel.org" Subject: Re: [PATCH 3/3] x86/MCE/AMD: Get address from already initialized block Message-ID: <20180516224641.GA31929@pd.tnic> References: <20180201184813.82253-1-Yazen.Ghannam@amd.com> <20180201184813.82253-3-Yazen.Ghannam@amd.com> <20180414004230.GA2033@probook> <20180416115624.GA1543@probook> <20180515093953.GA1746@probook> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20180515093953.GA1746@probook> User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, May 15, 2018 at 11:39:54AM +0200, Johannes Hirte wrote: > The out-of-bound access happens in get_block_address: > > if (bankp && bankp->blocks) { > struct threshold_block *blockp blockp = &bankp->blocks[block]; > > with block=1. This doesn't exists. I don't even find any array here. > There is a linked list, created in allocate_threshold_blocks. On my > system I get 17 lists with one element each. Yes, what a mess this is. ;-\ There's no such thing as ->blocks[block] array. We assign simply the threshold_block to it in allocate_threshold_blocks: per_cpu(threshold_banks, cpu)[bank]->blocks = b; And I can't say the design of this thing is really friendly but it is still no excuse that I missed that during review. Grrr. So, Yazen, what really needs to happen here is to iterate the bank->blocks->miscj list to find the block you're looking for and return its address, the opposite to this here: if (per_cpu(threshold_banks, cpu)[bank]->blocks) { list_add(&b->miscj, &per_cpu(threshold_banks, cpu)[bank]->blocks->miscj); } else { per_cpu(threshold_banks, cpu)[bank]->blocks = b; } and don't forget to look at ->blocks itself. And then you need to make sure that searching for block addresses still works when resuming from suspend so that you can avoid the RDMSR IPIs. Ok? -- Regards/Gruss, Boris. SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg) --