linux-kernel - Re: [bug] /etc/profile: line 30: /dev/null: Permission denied (Was: Re: [PATCH] Remove broken by design and by implementation devtmpfs maintenance disaster)

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Date:	Sun, 27 Sep 2009 15:52:20 -0700
From:	Greg KH <greg@...ah.com>
To:	Pavel Machek <pavel@....cz>
Cc:	Ingo Molnar <mingo@...e.hu>,
	Linus Torvalds <torvalds@...ux-foundation.org>,
	Kay Sievers <kay.sievers@...y.org>,
	"Eric W. Biederman" <ebiederm@...ssion.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [bug] /etc/profile: line 30: /dev/null: Permission denied
	(Was: Re: [PATCH] Remove broken by design and by implementation
	devtmpfs maintenance disaster)

On Fri, Sep 25, 2009 at 10:49:26PM +0200, Pavel Machek wrote:
> Hi!
> 
> > > > > > I've reproduced a bug with the following .config options:
> > > > > >
> > > > > > ??CONFIG_DEVTMPFS=y
> > > > > > ??CONFIG_DEVTMPFS_MOUNT=y
> > > > > >
> > > > > > /dev/null and /dev/zero are not read/writable to ordinary users, 
> > > > > > breaking normal bootup and login:
> > > > > 
> > > > > Udev should run long before some ordinary/non-root user can login, 
> > > > > and apply the permissions as it always does. It's known to work on 
> > > > > Fedora, SUSE, Ubuntu. What kind of system/environment/setup is that 
> > > > > where you see this?
> > > > 
> > > > I don't know if this is what Ingo does, but I have a few machines 
> > > > where I don't run the distro-supplied 'initrd' at all, because it's 
> > > > easier to boot without it. The Fedora initrd doesn't allow me to 
> > > > sanely set root filesystem parameters without totally rewriting the 
> > > > initrd image, which I'm not interested in, for example (they'll take 
> > > > effect for the root initrd, not the final root).
> > > 
> > > Correct: i'm booting raw bzImages, with /dev copied to the real /dev. To 
> > > this box udev is mostly an annoyance that slows down my bootup ;-)
> > 
> > I use non-initrd systems as well, and this option works for me on Gentoo
> > and SUSE machines.
> > 
> > As you are using a very old udev, and the boot infrastructure for udev
> > in older Fedora releases was a bit "odd" in places, I would recommend
> > not using these options on that machine.  If we need to reword the
> > Kconfig help option to make it a bit more clear, do you have a
> > suggestion on what we should change?
> 
> "no regressions" ?

It's now resolved, so there are no regressions :)

thanks,

greg k-h
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