Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756889AbYJJJl7 (ORCPT ); Fri, 10 Oct 2008 05:41:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752306AbYJJJlv (ORCPT ); Fri, 10 Oct 2008 05:41:51 -0400 Received: from courier.cs.helsinki.fi ([128.214.9.1]:33532 "EHLO mail.cs.helsinki.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751991AbYJJJlu (ORCPT ); Fri, 10 Oct 2008 05:41:50 -0400 Subject: [PROBLEM] hard-lock with kmemtrace, relayfs, and splice From: Pekka Enberg To: Eduard - Gabriel Munteanu Cc: zanussi@comcast.net, jens.axboe@oracle.com, linux-kernel@vger.kernel.org In-Reply-To: <1223629803.8959.40.camel@penberg-laptop> References: <20080923212914.GB5237@localhost> <1223386477.28348.42.camel@penberg-laptop> <1223623191.8959.26.camel@penberg-laptop> <1223628687.8959.37.camel@penberg-laptop> <1223629803.8959.40.camel@penberg-laptop> Date: Fri, 10 Oct 2008 12:42:03 +0300 Message-Id: <1223631723.8959.46.camel@penberg-laptop> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 7bit X-Mailer: Evolution 2.22.3.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1339 Lines: 40 (I'm cc'ing Tom, Jens, and LKML.) On Fri, 2008-10-10 at 12:10 +0300, Pekka Enberg wrote: > > I'm seeing a hard lock on my machine when I run kmemtraced with the > > following patch applied: > > > > http://git.kernel.org/?p=linux/kernel/git/penberg/slab-2.6.git;a=commitdiff;h=17ca1d5506b1db433f0b7167a627bfd55d319dd3 > > > > I can enable/disable kmemtrace via the debugfs files fine and can also > > read the relay files with cat. > > > > Any idea where this is coming from? > > OK, it's the first splice() call in reader_thread() that causes the > hang. Hmm. To recap, with a CONFIG_KMEMTRACE enabled kernel from the "topic/kmemtrace" branch of: git://git.kernel.org/pub/scm/linux/kernel/git/penberg/slab-2.6.git topic/kmemtrace running the "kmemtraced" program from git://git.kernel.org/pub/scm/linux/kernel/git/penberg/kmemtrace-user.git results to a hard lock on my machine. I am unable to find anything obviously wrong with it and as I can read/write the relay files just fine, I'm beginning to think it's problem in relayfs splice implementation. Tom, thoughts? Pekka -- 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/