From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756544AbZEFHzo (ORCPT ); Wed, 6 May 2009 03:55:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753707AbZEFHzf (ORCPT ); Wed, 6 May 2009 03:55:35 -0400 Received: from web32605.mail.mud.yahoo.com ([68.142.207.232]:24773 "HELO web32605.mail.mud.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753512AbZEFHze (ORCPT ); Wed, 6 May 2009 03:55:34 -0400 Message-ID: <957194.27869.qm@web32605.mail.mud.yahoo.com> X-YMail-OSG: L2G7pPkVM1nFo5k8wdtFGlzWUIR2SFEK.SZcnuExXWdJ_nREKh5P.6WOoGpLJlU0gSTfYrXs_imEIIVvki4XmBTh4Z513p3UcZHAymqTIGXJY_VbfwqLvq5fE9mMk3pIcUcRJ3AmzUvXqvOuLMcynbWlF2rLFmrswQLejZpX3HjbbcTUA1w3Kgs7oVVAVsvFu15.1FBE3.y1DNKHUM1v6cbw5Vu0dKkLSUEbcED70ZmHnnnvk594oglVJIuMfNSyq8z7QSKd5gdg0nrl25zXgh5ruRPp32Hn9jMdjCFE81LqNOUnv8Kl3AxIYALn6EhGbZaTzqwFNPWTxcsn_QMUl3VP X-RocketYMMF: knobi.rm X-Mailer: YahooMailRC/1277.35 YahooMailWebService/0.7.289.1 References: <409142.83316.qm@web32605.mail.mud.yahoo.com> <20090428182837.62c51f26.akpm@linux-foundation.org> <1240977096.5478.3.camel@marge.simson.net> <20090429011755.c141c599.akpm@linux-foundation.org> <20090429120827.GI8633@ZenIV.linux.org.uk> <1241014725.15095.19.camel@marge.simson.net> <20090505154911.e0309a4f.akpm@linux-foundation.org> <1241585140.5196.28.camel@marge.simson.net> Date: Wed, 6 May 2009 00:55:34 -0700 (PDT) From: Martin Knoblauch Subject: Re: Analyzed/Solved: Booting 2.6.30-rc2-git7 very slow To: Mike Galbraith , Andrew Morton Cc: viro@ZenIV.linux.org.uk, rjw@sisk.pl, linux-kernel@vger.kernel.org, tigran@aivazian.fsnet.co.uk In-Reply-To: <1241585140.5196.28.camel@marge.simson.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org ----- Original Message ---- > From: Mike Galbraith > To: Andrew Morton > Cc: viro@ZenIV.linux.org.uk; knobi@knobisoft.de; rjw@sisk.pl; linux-kernel@vger.kernel.org; tigran@aivazian.fsnet.co.uk > Sent: Wednesday, May 6, 2009 6:45:40 AM > Subject: Re: Analyzed/Solved: Booting 2.6.30-rc2-git7 very slow > > On Tue, 2009-05-05 at 15:49 -0700, Andrew Morton wrote: > > On Wed, 29 Apr 2009 16:18:45 +0200 > > Mike Galbraith wrote: > > > > > On Wed, 2009-04-29 at 13:08 +0100, Al Viro wrote: > > > > On Wed, Apr 29, 2009 at 01:17:55AM -0700, Andrew Morton wrote: > > > > > > > > > > > > Questions remains: was this intentional? It breaks existing > userspace and should therefore be considered a regression - right? On the other > hand, it will never be a problem for RHEL-4/5 kernels, unless the change in > 2.6.29 gets backported. Any ideas? > > > > > > > > > > > > > > afaik that was unintentional and was probably a mistake. > > > > > > > > > > > > > > I wonder how we did that. > > > > > > > > > > > > > > > > > > > [hotplug]# grep sysfs /proc/mounts > > > > > > > none /sys sysfs rw,relatime 0 0 > > > > > > > /sys /sys sysfs rw,relatime 0 0 > > > > > > > > > > > > ___(I wonder how the heck that is accomplished) > > > > > > > > > > Beats me. I'm not seeing likely changes in fs/proc/base.c or around > > > > > show_mountinfo(). Maybe sysfs broke in an ingenious way. (hopefully > > > > > cc's viro). > > > > > > > > Er... Somebody mounting sysfs twice? From some init script and from > > > > /etc/fstab, perhaps? That definitely looks like two mount(2) had to > > > > have been done to cause that... > > > > > > Yeah, but how does one go about doing that? > > > > > > Using mount -f, I can convince mount to succeed, but I still have only > > > one entry in /proc/mounts, despite what my mount binary imagines. > > > > > > marge:..sys/vm # grep sysfs /proc/mounts > > > sysfs /sys sysfs rw,relatime 0 0 > > > > > > marge:..sys/vm # mount|grep sysfs > > > sysfs on /sys type sysfs (rw) > > > sys on /sys type sysfs (rw) > > > /sys on /sys type sysfs (rw) > > > > > > > So /proc/mounts is OK and /etc/mtab is wrong? > > > > Obvious next step is to strace `mount -f', see what's happening around > > sys_mount(), please. > > Well, there is no syscall with -f. > > I was trying various mount options to see if I could find a way to > create bogons that could confuse scripts. I could create bogons > in /etc/mtab with -f, or bogons in /proc/mounts by using --move. I > could re-create the exact reported data with a combination of mount -n > and mount --move. I could not get a double /proc/mounts entry without > --move, and that seems unlikely to appear in boot scripts. So I still > wonder how the heck it was accomplished. > > I also now wonder why you can --move mounts on top of one another, but > beck with it, ignorance conserves braincells I may some day need :) > just to bring this back to my problem :-) Last week I reported that the "new" sysfs entry in /proc/mounts already comes out of initrd. Does this ring a bell? http://lkml.indiana.edu/hypermail/linux/kernel/0904.3/03048.html Cheers Martin