on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Ricardo Martins]

I'm using Linux kernel 2.4.10, and since the fatidic 2.4.11 release ( i 
tried 2.4.11 (one day :)))) 2.4.12, 2.4.13 and 2.4.14-pre6) I get the 
same bug on and on (that means I can reproduce the experience and obtain 
the same results).

Procedure
In X windows (version 4.1.0 compiled from the sources) when writing 
"exit" in xterm to close the terminal emulator, the window freezes, and 
from that moment on, every process becomes "unkillable", including xterm 
and X (ps also freezes), and there's no way to shutdown GNU/Linux in a 
sane way (must hit reset or poweroff).

Environment
I used Glibc 2.2.4 and GCC 3.0.1 (tried with 2.95.3, obtained the same 
results).

The odd thing is, that with the same configuration, kernel 2.4.10 works 
just fine, but every other release since then ends up doing the same 
thing (the system can't maintain integrity after writing "exit" and 
hiting enter in xterm).

Please help me, I getting slightly mad with the situation.

Ricardo Martins

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Pierre Rousselet]

Ricardo Martins wrote:


> Procedure
> In X windows (version 4.1.0 compiled from the sources) when writing 
> "exit" in xterm to close the terminal emulator, the window freezes, and 
> from that moment on, every process becomes "unkillable", including xterm 
> and X (ps also freezes), and there's no way to shutdown GNU/Linux in a 
> sane way (must hit reset or poweroff).


I can see the problem here with 2.4.13. I don't know if it's kernel 
related, I'm used using rxvt, never xterm.

It looks like xterm takes the terminal where you started X from.

Are you using devfs ?


Pierre


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

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Ricardo Martins]

 >> Procedure
 >> In X windows (version 4.1.0 compiled from the sources) when writing
 >> "exit" in xterm to close the terminal emulator, the window freezes, and
 >> from that moment on, every process becomes "unkillable", including 
xterm
 >> and X (ps also freezes), and there's no way to shutdown GNU/Linux in a
 >> sane way (must hit reset or poweroff).


 >I can see the problem here with 2.4.13. I don't know if it's kernel
 >related, I'm used using rxvt, never xterm.

 >It looks like xterm takes the terminal where you started X from.

 >Are you using devfs ?


 >Pierre


Pierre, yes, i'm using devfs that seems to be the problem, do you know 
how to fix it ?

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Pierre Rousselet]

Ricardo Martins wrote:

>  >> Procedure
>  >> In X windows (version 4.1.0 compiled from the sources) when writing
>  >> "exit" in xterm to close the terminal emulator, the window freezes, and
>  >> from that moment on, every process becomes "unkillable", including 
> xterm
>  >> and X (ps also freezes), and there's no way to shutdown GNU/Linux in a
>  >> sane way (must hit reset or poweroff).
> 
> 
>  >I can see the problem here with 2.4.13. I don't know if it's kernel
>  >related, I'm used using rxvt, never xterm.
> 
>  >It looks like xterm takes the terminal where you started X from.
> 
>  >Are you using devfs ?
> 
> 
>  >Pierre
> 
> 
> Pierre, yes, i'm using devfs that seems to be the problem, do you know 
> how to fix it ?
 
Is it devfs or xterm which needs to be fixed ? I would

suggest to switch to rxvt which works fine with/without devfs.


Pierre

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

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Nick LeRoy]

On Thursday 01 November 2001 13:31, Pierre Rousselet wrote:
> Ricardo Martins wrote:
> >  >> Procedure
> >  >> In X windows (version 4.1.0 compiled from the sources) when writing
> >  >> "exit" in xterm to close the terminal emulator, the window freezes,
> >  >> and from that moment on, every process becomes "unkillable",
> >  >> including
> >
> > xterm
> >
> >  >> and X (ps also freezes), and there's no way to shutdown GNU/Linux in
> >  >> a sane way (must hit reset or poweroff).
> >  >
> >  >I can see the problem here with 2.4.13. I don't know if it's kernel
> >  >related, I'm used using rxvt, never xterm.
> >  >
> >  >It looks like xterm takes the terminal where you started X from.
> >  >
> >  >Are you using devfs ?
> >  >
> >  >
> >  >Pierre
> >
> > Pierre, yes, i'm using devfs that seems to be the problem, do you know
> > how to fix it ?
>
> Is it devfs or xterm which needs to be fixed ? I would
>
> suggest to switch to rxvt which works fine with/without devfs.

With all due respect, I'd have to differ.....  Do you have any idea how many 
people are running how many copies of xterm as we speak?  Even if we pair 
that down to all those running devfs, it's certainly a substantial number.  
The kernel should, above all else, run old applications without breaking them.

-Nick

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Pierre Rousselet]

Nick LeRoy wrote:

> On Thursday 01 November 2001 13:31, Pierre Rousselet wrote:
> 
>>Ricardo Martins wrote:
>>
>>> >> Procedure
>>> >> In X windows (version 4.1.0 compiled from the sources) when writing
>>> >> "exit" in xterm to close the terminal emulator, the window freezes,
>>> >> and from that moment on, every process becomes "unkillable",
>>> >> including
>>>
>>>xterm
>>>
>>> >> and X (ps also freezes), and there's no way to shutdown GNU/Linux in
>>> >> a sane way (must hit reset or poweroff).
>>> >
>>> >I can see the problem here with 2.4.13. I don't know if it's kernel
>>> >related, I'm used using rxvt, never xterm.
>>> >
>>> >It looks like xterm takes the terminal where you started X from.
>>> >
>>> >Are you using devfs ?
>>> >
>>> >
>>> >Pierre
>>>
>>>Pierre, yes, i'm using devfs that seems to be the problem, do you know
>>>how to fix it ?
>>>
>>Is it devfs or xterm which needs to be fixed ? I would
>>
>>suggest to switch to rxvt which works fine with/without devfs.
>>
> 
> With all due respect, I'd have to differ.....  Do you have any idea how many 
> people are running how many copies of xterm as we speak?  Even if we pair 
> that down to all those running devfs, it's certainly a substantial number.  
> The kernel should, above all else, run old applications without breaking them.
> 
> -Nick


devfs is still marked EXPERIMENTAL in the kernel building. If you select it you

must be prepared to tolerate some misbehaviour. rxvt is not newer than 
xterm, it is lighter.

Pierre



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

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Nick LeRoy]

On Thursday 01 November 2001 14:00, Pierre Rousselet wrote:
> Nick LeRoy wrote:
> > On Thursday 01 November 2001 13:31, Pierre Rousselet wrote:
> >>Ricardo Martins wrote:
> >>> >> Procedure
> >>> >> In X windows (version 4.1.0 compiled from the sources) when writing
> >>> >> "exit" in xterm to close the terminal emulator, the window freezes,
> >>> >> and from that moment on, every process becomes "unkillable",
> >>> >> including
> >>>
> >>>xterm
> >>>
> >>> >> and X (ps also freezes), and there's no way to shutdown GNU/Linux in
> >>> >> a sane way (must hit reset or poweroff).
> >>> >
> >>> >I can see the problem here with 2.4.13. I don't know if it's kernel
> >>> >related, I'm used using rxvt, never xterm.
> >>> >
> >>> >It looks like xterm takes the terminal where you started X from.
> >>> >
> >>> >Are you using devfs ?
> >>> >
> >>> >
> >>> >Pierre
> >>>
> >>>Pierre, yes, i'm using devfs that seems to be the problem, do you know
> >>>how to fix it ?
> >>
> >>Is it devfs or xterm which needs to be fixed ? I would
> >>
> >>suggest to switch to rxvt which works fine with/without devfs.
> >
> > With all due respect, I'd have to differ.....  Do you have any idea how
> > many people are running how many copies of xterm as we speak?  Even if we
> > pair that down to all those running devfs, it's certainly a substantial
> > number. The kernel should, above all else, run old applications without
> > breaking them.
> >
> > -Nick
>
> devfs is still marked EXPERIMENTAL in the kernel building. If you select it
> you
>
> must be prepared to tolerate some misbehaviour. rxvt is not newer than
> xterm, it is lighter.

Marked experiment, for now.  What about when it's no longer "experimental"?  
Configuring a kernel to enable such a feature should *not* break 
applications, especially something as prolific as xterm.

-Nick

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Jeffrey W. Baker]

On Thu, 1 Nov 2001, Nick LeRoy wrote:

> Marked experiment, for now.  What about when it's no longer "experimental"?
> Configuring a kernel to enable such a feature should *not* break
> applications, especially something as prolific as xterm.

Are you sure you know what you are talking about?  Devfs causes this
problem because of a defect, not by design.  It is marked experimental
because it's loaded with such defects.  Don't use it until the
experimental tag is removed, if you are not prepared for some malfunction.

-jwb

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Nick LeRoy]

On Thursday 01 November 2001 14:13, you wrote:
> On Thu, 1 Nov 2001, Nick LeRoy wrote:
> > Marked experiment, for now.  What about when it's no longer
> > "experimental"? Configuring a kernel to enable such a feature should
> > *not* break applications, especially something as prolific as xterm.
>
> Are you sure you know what you are talking about?  Devfs causes this
> problem because of a defect, not by design.  It is marked experimental
> because it's loaded with such defects.  Don't use it until the
> experimental tag is removed, if you are not prepared for some malfunction.

Yeah, I think that I know what I'm talking about.  The question was:  Should 
devfs be fixed, or should xterm be fixed.  I don't know how serious it is, or 
exactly what the nature of the problem is (haven't followed the thread that 
closely), but, from the "mile high" point of view, this defect, be it design 
or just a one-line bug, needs to be fixed before it can be tagged 
"non-experimental".  I don't understand why people would think otherwise, to 
be honest.

-Nick

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Rik van Riel]

On Thu, 1 Nov 2001, Nick LeRoy wrote:

> Yeah, I think that I know what I'm talking about.  The question
> was:  Should devfs be fixed, or should xterm be fixed.

If any random malicious user can crash the machine through
devfs, I think the answer to this question is quite obvious.

The security hole should be fixed.

Rik
-- 
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Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Richard Gooch]

Rik van Riel writes:
> On Thu, 1 Nov 2001, Nick LeRoy wrote:
> 
> > Yeah, I think that I know what I'm talking about.  The question
> > was:  Should devfs be fixed, or should xterm be fixed.
> 
> If any random malicious user can crash the machine through
> devfs, I think the answer to this question is quite obvious.
> 
> The security hole should be fixed.

Agreed. I will.

				Regards,

					Richard....
Permanent: rgooch@atnf.csiro.au
Current:   rgooch@ras.ucalgary.ca

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[David Ford]

You should censor those words ;)  You wouldn't want us Americans knowing 
about it.

"The <censored> should be fixed."

David

Rik van Riel wrote:

>On Thu, 1 Nov 2001, Nick LeRoy wrote:
>
>>Yeah, I think that I know what I'm talking about.  The question
>>was:  Should devfs be fixed, or should xterm be fixed.
>>
>
>If any random malicious user can crash the machine through
>devfs, I think the answer to this question is quite obvious.
>
>The security hole should be fixed.
>
>Rik
>

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Brian Gerst]

Nick LeRoy wrote:
> 
> On Thursday 01 November 2001 14:13, you wrote:
> > On Thu, 1 Nov 2001, Nick LeRoy wrote:
> > > Marked experiment, for now.  What about when it's no longer
> > > "experimental"? Configuring a kernel to enable such a feature should
> > > *not* break applications, especially something as prolific as xterm.
> >
> > Are you sure you know what you are talking about?  Devfs causes this
> > problem because of a defect, not by design.  It is marked experimental
> > because it's loaded with such defects.  Don't use it until the
> > experimental tag is removed, if you are not prepared for some malfunction.
> 
> Yeah, I think that I know what I'm talking about.  The question was:  Should
> devfs be fixed, or should xterm be fixed.  I don't know how serious it is, or
> exactly what the nature of the problem is (haven't followed the thread that
> closely), but, from the "mile high" point of view, this defect, be it design
> or just a one-line bug, needs to be fixed before it can be tagged
> "non-experimental".  I don't understand why people would think otherwise, to
> be honest.

Fix devfs.  If the kernel lets a user program crash it, it's a kernel
bug.

--

				Brian Gerst

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Dr. Kelsey Hudson]

On Thu, 1 Nov 2001, Nick LeRoy wrote:
> Marked experiment, for now.  What about when it's no longer "experimental"?  
> Configuring a kernel to enable such a feature should *not* break 
> applications, especially something as prolific as xterm.

Well, we would hope it's fixed by then, wouldn't we? How about you fix it 
and send us the patch? :)

 Kelsey Hudson                                           khudson@ctica.com 
 Software Engineer
 Compendium Technologies, Inc                               (619) 725-0771
---------------------------------------------------------------------------     

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Ricardo Martins]

Pierre, thanks for the advice.

If the problem is with xterm, it sure kicks "Linux Stability" in the 
face. Maybe (and I hope) the problem is in devfs.

Ricardo Martins

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Per Lidén]

On Thu, 1 Nov 2001, Ricardo Martins wrote:

[...]
> If the problem is with xterm, it sure kicks "Linux Stability" in the
> face. Maybe (and I hope) the problem is in devfs.

xterm is not the problem, it's devfs' locking ema which results in a
deadlock.

/Per

Re: on exit xterm totally wrecks linux 2.4.11 to 2.4.14-pre6 (unkillable processes)

[Chris Rankin]

Hi,

I see something similar with vanilla 2.4.13 (+devfs), except my 
unkillable xterms don't appear until a modprobe has already failed. 
Specifically, what seems to happen is:

- an open() call causes the kernel to grab the devfs rwsem for reading, 
and then load a module (e.g. ide-cd).
- the modprobe process then waits forever for write-access to the devfs 
rwsem.

Each xterm then waits forever in "wait_for_devfsd_finished()", 
presumably when it tries to close its terminal.

Are you also using dynamic module loading? Are ALL of your unkillable 
processes xterms, or do you also have a failed modprobe lurking somewhere?

Chris