From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f179.google.com (mail-wi0-f179.google.com [209.85.212.179]) by kanga.kvack.org (Postfix) with ESMTP id 87A356B0082 for ; Wed, 16 Apr 2014 13:58:41 -0400 (EDT) Received: by mail-wi0-f179.google.com with SMTP id z2so1801795wiv.0 for ; Wed, 16 Apr 2014 10:58:41 -0700 (PDT) Received: from alpha.arachsys.com (alpha.arachsys.com. [2001:9d8:200a:0:9f:9fff:fe90:dbe3]) by mx.google.com with ESMTPS id h8si5500345wiw.78.2014.04.16.10.58.40 for (version=TLSv1 cipher=RC4-SHA bits=128/128); Wed, 16 Apr 2014 10:58:40 -0700 (PDT) Date: Wed, 16 Apr 2014 18:58:37 +0100 From: Richard Davies Subject: Re: Kernel crash triggered by dd to file with memcg, worst on btrfs Message-ID: <20140416175837.GA9412@alpha.arachsys.com> References: <20140416174210.GA11486@alpha.arachsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140416174210.GA11486@alpha.arachsys.com> Sender: owner-linux-mm@kvack.org List-ID: To: cgroups@vger.kernel.org, linux-mm@kvack.org, linux-btrfs@vger.kernel.org Richard Davies wrote: > I have a test case in which I can often crash an entire machine by running > dd to a file with a memcg with relatively generous limits. This is > simplified from real world problems with heavy disk i/o inside containers. > > The crashes are easy to trigger when dding to create a file on btrfs. On > ext3, typically there is just an error in the kernel log, although > occasionally it also crashes. A further note - the ext3 SLUB errors occur when dding into a ext3 file alone. The few ext3 crashes occurred when dding into a btrfs file for a while without a crash, then switching to dding into an ext3 file. So the "ext3 crashes" could actually be due to btrfs cached data still in memory - i.e. all crashes could be due to btrfs use. Richard. -- 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