From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-la0-f44.google.com (mail-la0-f44.google.com [209.85.215.44]) by kanga.kvack.org (Postfix) with ESMTP id E62386B0069 for ; Mon, 13 Oct 2014 16:22:40 -0400 (EDT) Received: by mail-la0-f44.google.com with SMTP id hs14so7376254lab.3 for ; Mon, 13 Oct 2014 13:22:40 -0700 (PDT) Received: from smtp2.it.da.ut.ee (smtp2.it.da.ut.ee. [2001:bb8:2002:500:20f:1fff:fe04:1bbb]) by mx.google.com with ESMTP id wn2si23703012lbb.96.2014.10.13.13.22.38 for ; Mon, 13 Oct 2014 13:22:39 -0700 (PDT) Date: Mon, 13 Oct 2014 23:22:37 +0300 (EEST) From: mroos@linux.ee Subject: Re: unaligned accesses in SLAB etc. In-Reply-To: <20141012.132012.254712930139255731.davem@davemloft.net> Message-ID: References: <20141011.221510.1574777235900788349.davem@davemloft.net> <20141012.132012.254712930139255731.davem@davemloft.net> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org List-ID: To: David Miller Cc: Linux Kernel list , cl@linux.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, akpm@linux-foundation.org, linux-mm@kvack.org, sparclinux@vger.kernel.org > 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] -- Meelis Roos (mroos@linux.ee) -- 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