Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754129AbaJMXv4 (ORCPT ); Mon, 13 Oct 2014 19:51:56 -0400 Received: from LGEMRELSE7Q.lge.com ([156.147.1.151]:51516 "EHLO lgemrelse7q.lge.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754022AbaJMXvy (ORCPT ); Mon, 13 Oct 2014 19:51:54 -0400 X-Original-SENDERIP: 10.177.222.213 X-Original-MAILFROM: iamjoonsoo.kim@lge.com Date: Tue, 14 Oct 2014 08:52:19 +0900 From: Joonsoo Kim To: mroos@linux.ee Cc: David Miller , Linux Kernel list , cl@linux.com, penberg@kernel.org, rientjes@google.com, akpm@linux-foundation.org, linux-mm@kvack.org, sparclinux@vger.kernel.org Subject: Re: unaligned accesses in SLAB etc. Message-ID: <20141013235219.GA11191@js1304-P5Q-DELUXE> References: <20141011.221510.1574777235900788349.davem@davemloft.net> <20141012.132012.254712930139255731.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 13, 2014 at 11:22:37PM +0300, mroos@linux.ee wrote: > > From: David Miller > > Date: Sat, 11 Oct 2014 22:15:10 -0400 (EDT) > > > > > > > > I'm getting tons of the following on sparc64: > > > > > > [603965.383447] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0 > > > [603965.396987] Kernel unaligned access at TPC[546b60] free_block+0xa0/0x1a0 > > > [603965.410523] Kernel unaligned access at TPC[546b58] free_block+0x98/0x1a0 > > > In all of the cases, the address is 4-byte aligned but not 8-byte > > aligned. And they are vmalloc addresses. > > > > Which made me suspect the percpu commit: > > > > ==================== > > commit bf0dea23a9c094ae869a88bb694fbe966671bf6d > > Author: Joonsoo Kim > > Date: Thu Oct 9 15:26:27 2014 -0700 > > > > mm/slab: use percpu allocator for cpu cache > > ==================== > > > > And indeed, reverting this commit fixes the problem. > > I tested Joonsoo Kim's fix and it gets rid of the kernel unaligned > access messages, yes. > > But the instability on UltraSparc II era machines still remains - > occassional Bus Errors during kernel compilation, messages like this: > > sh[11771]: segfault at ffd6a4d1 ip 00000000f7cc5714 (rpc 00000000f7cc562c) sp 00000000ffd69d90 error 30002 in libc-2.19.so[f7c44000+16a000] Hello, Meelis. Thanks for testing. I'd like to know that your another problem is related to commit bf0dea23a9c0 ("mm/slab: use percpu allocator for cpu cache"). So, if the commit is reverted, your another problem is also gone completely? Thanks. -- 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/