From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f178.google.com (mail-pd0-f178.google.com [209.85.192.178]) by kanga.kvack.org (Postfix) with ESMTP id 58A896B0069 for ; Mon, 13 Oct 2014 19:51:56 -0400 (EDT) Received: by mail-pd0-f178.google.com with SMTP id y10so6495212pdj.9 for ; Mon, 13 Oct 2014 16:51:56 -0700 (PDT) Received: from lgemrelse7q.lge.com (LGEMRELSE7Q.lge.com. [156.147.1.151]) by mx.google.com with ESMTP id hc9si11481293pac.184.2014.10.13.16.51.53 for ; Mon, 13 Oct 2014 16:51:54 -0700 (PDT) Date: Tue, 14 Oct 2014 08:52:19 +0900 From: Joonsoo Kim 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: Sender: owner-linux-mm@kvack.org List-ID: 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 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org