Re: 2.5.1-pre5 not easy to boot with devfs

[Pierre Rousselet <pierre.rousselet@wanadoo.fr>]

Richard Gooch wrote:

 
> I assume if you use kernel 2.4.16 with devfsd-1.3.20 that there is no
> Oops?

No there is no oops with 2.4.16, BUT I am sure CONFIG_DEBUG_KERNEL is
not set in my kernel 2.4.16. I shall try to re-compile it with it.

2.5.1-pre5 is fine as well, provided that you don't say yes to
CONFIG_DEBUG_KERNEL.

>ksymoops 2.4.3 on i686 2.5.1-pre5.  Options used
>     -V (default)
>     -k /proc/ksyms (default)
>     -l /proc/modules (default)
>     -o /lib/modules/2.5.1-pre5/ (default)
>     -m /usr/src/linux/System.map (default)
> Did you install the appropriate System.map in /usr/src/linux? If not,

I am building linux in /usr/gnu/linux. There is only one file in
/usr/src/linux, the System.map I put before running ksymoops.

> > > Edit your /etc/fstab and remove the line for devfs. You don't
> > > need/want that if you have CONFIG_DEVFS_MOUNT=y.
> >
> > no problem
> I assume that didn't help. It would be helpful if you said so
> explicitely.

I have now removed this line in fstab. It was useful when /dev had
permanent device files. With devfs only it's not needed but it doesn't
improve.
 
> I'm not asking you to give up using NVidia drivers forever, but it's
> very important that those drivers are not loaded until the Oops has
> happened, you've captured the boot messages, run them through ksymoops
> and either mailed them to me, or at the very least saved them to a
> file for later emailing. By moving the NVidia drivers, you ensure that
> they aren't autoloaded prior to Oops generation and debug capturing.
> 
> If you're unwilling to move those drivers elsewhere (I don't see why
> this is a problem for you: you can live without them for a few
> minutes), then neither I nor anyone else on this list can or will help
> you. Binary-only drivers like NVidia cause no end of problems, and
> kernels with them loaded (or even once loaded and then unloaded) are
> not debuggable by the community. For all I know, the NVidia driver
> abuses devfs in some way, and there isn't a bug in devfs itself. But
> not having the source, *I can't be sure*. And since I don't know, I
> can't help.
> 
> Just why are you unwilling to move those drivers?

You misundertood me. I would never include in the kernel a binary driver
which would break at each new release of linux. 
 
> > > prevent their being loaded. Even if you load but don't use such
> > > drivers, they still make debugging information unreliable.
> > >
> > > I've had a look at the code, and I see no reason for devfs to fail in
> > > this way, unless some driver is abusing it.
> >
> > I would suspect 1st devfsd. 2.4.16 is not happy at all with
> > devfsd-1.3.20, even rxvt fails to find a terminal.
> 
> Devfsd is just a user-space process, and can't cause an Oops unless
> there is a kernel bug (i.e. a devfs bug, or maybe a driver bug). I
> believe that devfsd-v1.3.20 should not make it more likely to get an
> Oops than when using devfsd-1.3.18. If devfsd-v1.3.20 really does
> trigger an Oops while 1.3.18 doesn't then please try 1.3.19 and report
> the results.
> 
> A separate issue is why rxvt doesn't work. Again, it's important to
> try devfsd-v1.3.19 to see if that also breaks rxvt. If so, report and
> also send a strace output of rxvt so I can see what's going wrong
> there.
> 
> Finally, please try kernel 2.4.17-pre1, which has the latest version
> of devfs. The 2.5.1-pre kernels have a lot of new experimental code
> which could be causing some of the problems. By using 2.4.17, it
> limits the changes to (mostly) devfs, so limits the variables. When
> you use 2.5.1, I can't tell if there is a bug in devfs, or perhaps
> some driver which is doing something illegal with devfs.


Pierre
-- 
------------------------------------------------
 Pierre Rousselet <pierre.rousselet@wanadoo.fr>
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