Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759530Ab1D0Qyj (ORCPT ); Wed, 27 Apr 2011 12:54:39 -0400 Received: from rcsinet10.oracle.com ([148.87.113.121]:64793 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751758Ab1D0Qyi (ORCPT ); Wed, 27 Apr 2011 12:54:38 -0400 Content-Type: text/plain; charset=UTF-8 From: Chris Mason To: James Bottomley Cc: linux-fsdevel , linux-mm , linux-kernel Subject: Re: [BUG] fatal hang untarring 90GB file, possibly writeback related. In-reply-to: <1303923000.2583.8.camel@mulgrave.site> References: <1303920553.2583.7.camel@mulgrave.site> <1303921583-sup-4021@think> <1303923000.2583.8.camel@mulgrave.site> Date: Wed, 27 Apr 2011 12:54:26 -0400 Message-Id: <1303923177-sup-2603@think> User-Agent: Sup/git Content-Transfer-Encoding: 8bit X-Source-IP: rcsinet15.oracle.com [148.87.113.117] X-Auth-Type: Internal IP X-CT-RefId: str=0001.0A090205.4DB84A4B.002C:SCFMA4539811,ss=1,fgs=0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1344 Lines: 31 Excerpts from James Bottomley's message of 2011-04-27 12:50:00 -0400: > On Wed, 2011-04-27 at 12:33 -0400, Chris Mason wrote: > > Probably easier to debug with a sysrq-l and sysrq-w. > > Yes, just enabling them for the repro ... I didn't echo 1 > > /proc/sys/kernel/sysrq first time around > > > If you get stuck > > on the filesystem, it is probably waiting on ram, which it probably > > can't get because kswapd is spinning. Eventually everyone backs up > > waiting for the transaction that never ends. If we're really lucky it > > is just GFP_KERNEL where it should NOFS. > > > > Since you're often stuck in different spots inside shrink_slab, we're > > probably not stuck on a lock. But, trying with lock debugging, lockdep > > enabled and preempt on is a good idea to rule out locking mistakes. > > > > Does the fedora debug kernel enable preempt? > > No ... I've taken the Fedora 15 kernel config directly from their > install CD for this (with a bit of munging to get it to work on -rc4) Ok, I'd try turning it on so we catch the sleeping with a spinlock held case better. -chris -- 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/