From: Theodore Tso Subject: Re: Segfaults--they're back! Date: Thu, 10 Jul 2008 07:02:30 -0400 Message-ID: <20080710110230.GA8603@mit.edu> References: <3.0.6.32.20080709150004.01bd9858@pop.west.cox.net> <20080710052150.GC6764@skywalker> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Gary Hawco , "linux-ext4@vger.kernel.org" , Mingming To: "Aneesh Kumar K.V" Return-path: Received: from www.church-of-our-saviour.ORG ([69.25.196.31]:44234 "EHLO thunker.thunk.org" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753264AbYGJLDG (ORCPT ); Thu, 10 Jul 2008 07:03:06 -0400 Content-Disposition: inline In-Reply-To: <20080710052150.GC6764@skywalker> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Thu, Jul 10, 2008 at 10:51:50AM +0530, Aneesh Kumar K.V wrote: > On Wed, Jul 09, 2008 at 03:00:04PM +0000, Gary Hawco wrote: > > Segfaults have returned with snapshots compiled after 070908--0010hrs GMT. > > > > That one worked fine. Is this a kernel or userspace segfault? i.e., is there a kernel oops message? If so, can you send us the oops message? It's really really useful to have it. Also, can you send us a dumpe2fs of the filesystem which ou were writing to? Some of the bugs which we've been finding are specific to a 1k block filesystem, for example, and sometimes that can help narrow down the bug. > Is your file system full when this happens ? Which user space call cause > the segfault ? An strace should be able to help you find that. We > actually have modified ext4 to give SIGBUS when we hit ENOSPC during > mmap write. For ex: > > root:/ext4# /root/mmaptest ./test4 0 100 > mmaping 0 to 100 > Bus error (core dumped) > root:/ext4# What Aneesh is talking about here is a userspace core dump which is normal, if the filesystem is full. I'm not sure that's what you're referring to assuming that "they're back" means you're referring to a kernel oops. Regards, - Ted