From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755339AbYADA40 (ORCPT ); Thu, 3 Jan 2008 19:56:26 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752408AbYADA4Q (ORCPT ); Thu, 3 Jan 2008 19:56:16 -0500 Received: from g1t0028.austin.hp.com ([15.216.28.35]:47055 "EHLO g1t0028.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752036AbYADA4P (ORCPT ); Thu, 3 Jan 2008 19:56:15 -0500 Subject: Re: Error returns not handled correctly by sysfs.c:subsys_attr_store() From: Andrew Patterson To: Tejun Heo Cc: Greg KH , Andrew Morton , linux-kernel@vger.kernel.org, linux-hotplug@vger.kernel.org, bjorn.helgaas@hp.com In-Reply-To: <1199405830.7025.33.camel@bluto.andrew> References: <1195683419.16019.225.camel@grinch> <20071126203116.0c93cdb9.akpm@linux-foundation.org> <20071127053321.GA975@kroah.com> <474D1BD4.2050805@suse.de> <1196278300.5431.9.camel@grinch> <474E10CF.7050009@suse.de> <1196716558.20124.179.camel@bluto.andrew> <1199404273.7025.21.camel@bluto.andrew> <477D78BE.1060404@suse.de> <1199405830.7025.33.camel@bluto.andrew> Content-Type: text/plain Date: Thu, 03 Jan 2008 17:56:13 -0700 Message-Id: <1199408174.7025.40.camel@bluto.andrew> Mime-Version: 1.0 X-Mailer: Evolution 2.12.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2008-01-03 at 17:17 -0700, Andrew Patterson wrote: > On Fri, 2008-01-04 at 09:07 +0900, Tejun Heo wrote: > > Hello, > > > > Andrew Patterson wrote: > > > It looks like this is a shell issue. After looking through the sysfs > > > code, I realized that this problem seems to be driven from user-land. > > > So I performed some experiments: > > > > > > 1. Wrote a simple program that just used write(2) to write to the > > > sysfs entry. This works fine. > > > 2. Used /bin/echo instead of the built-in echo command. This too > > > works fine. > > > 3. Tried several shells. Zsh and Bash both fail. Csh works fine. > > > > > > I then ran strace on the following shell-script: > > > > > > #!/bin/bash > > > > > > echo x > allow_restart > > > echo y > allow_restart > > > echo z > allow_restart > > > > > > and got: > > > > > > # strace -e trace=write ~/tmp/tester.sh > > > write(1, "x\n", 2) = -1 EINVAL (Invalid argument) > > > write(1, "x\n", 2) = -1 EINVAL (Invalid argument) > > > write(2, "/home/andrew/tmp/tester.sh: line"..., 72/home/andrew/tmp/tester.sh: line 4: echo: write error: Invalid argument > > > ) = 72 > > > write(1, "x\ny\n", 4) = -1 EINVAL (Invalid argument) > > > write(1, "x\ny\n", 4) = -1 EINVAL (Invalid argument) > > > write(2, "/home/andrew/tmp/tester.sh: line"..., 72/home/andrew/tmp/tester.sh: line 5: echo: write error: Invalid argument > > > ) = 72 > > > write(1, "x\ny\nz\n", 6) = -1 EINVAL (Invalid argument) > > > write(1, "x\ny\nz\n", 6) = -1 EINVAL (Invalid argument) > > > write(2, "/home/andrew/tmp/tester.sh: line"..., 72/home/andrew/tmp/tester.sh: line 6: echo: write error: Invalid argument > > > ) = 72 > > > write(1, "x\ny\nz\n", 6x > > > y > > > z > > > ) = 6 > > > Process 3800 detached > > > > Eeeeeeeekkkk.... That's scary. Which distro are you using and what does > > 'bash --version' say? > > IA64 Debian lenny. > > # bash --version > GNU bash, version 3.1.17(1)-release (ia64-unknown-linux-gnu) > > # zsh --version > zsh 4.3.4 (ia64-unknown-linux-gnu) > > # csh --version > tcsh 6.14.00 (Astron) 2005-03-25 (ia64-unknown-linux) options > wide,nls,dl,al,kan,rh,nd,color,filec > > I suppose I should try this an ia32 box again, and perhaps with some > other distros. I am not sure what the kernel can do about this, but it > might be nice to report it to the shell maintainers. Some further tests: AMD running Debian lenny with i686 kernel -- fails. Bash version = 3.1.17(1) Intel running Ubuntu/gutsy with i686 kernel -- fails. Bash version = 3.2.25(1) Itanium running SLES10 with ia64 kernel -- succeeds. Bash version = 3.1.17(1) BTW, I found a way to reproduce this without modifying the kernel. The /sys/class/scsi_host/*/state sysfs store routine returns EINVAL if an invalid state is written. So just echo 2 bad values to the the state sysfs entry while running strace. Andrew -- Andrew Patterson Hewlett-Packard Company