Reading Bad DVD Under 2.6.10 freezes the box.

Reading Bad DVD Under 2.6.10 freezes the box.

[Justin Piszcz]

I have a DVD where I have three files on it, (1.7gb,1.7gb,900mb).

On W2K, when I try to copy the second file, I get a BadCRC error message.

Under Linux, I copy up to about 860MB (watched via pipebench) and then it 
freezes the machine, I cannot ping or get to it or do anything on the 
console; instead, I am forced to hard reboot.

Main Question >> Why does Linux 'freeze up' when W2K gives a BadCRC error 
msg (never freezes)?

The DVD FS is Joilet+ISO (hence, why none of the files are bigger than 
2GB), is this normal?  Or is there no checking code when there are errors 
on DVD's to kill the read/etc so it does not freeze the box?

Thanks.

Re: Reading Bad DVD Under 2.6.10 freezes the box.

[linux-os]

On Mon, 7 Feb 2005, Justin Piszcz wrote:

> I have a DVD where I have three files on it, (1.7gb,1.7gb,900mb).
>
> On W2K, when I try to copy the second file, I get a BadCRC error message.
>
> Under Linux, I copy up to about 860MB (watched via pipebench) and then it 
> freezes the machine, I cannot ping or get to it or do anything on the 
> console; instead, I am forced to hard reboot.
>

Okay. You need to provide linux-kernel with the kind of
CD, and the drivers installed to support it.


> Main Question >> Why does Linux 'freeze up' when W2K gives a BadCRC error msg 
> (never freezes)?

Of course it should not. However, there were many incomplete changes
made in 2.6.nn and some may involve problems with locking, etc.

For instance an ioctl() call in 2.6.10 occurs with a kernel
lock being held. A lot of CD I/O is handled using ioctl() functions.
There may be an incompatibility (called a race) with certain
things that wait in the driver when the BKL (kernel lock) is
held.

>
> The DVD FS is Joilet+ISO (hence, why none of the files are bigger than 2GB), 
> is this normal?  Or is there no checking code when there are errors on DVD's 
> to kill the read/etc so it does not freeze the box?
>
> Thanks.
> -

If possible, reboot your system with 2.4.20-or-greater and see
if the CD subsystem behaves properly with a bad CD.


Cheers,
Dick Johnson
Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
  Notice : All mail here is now cached for review by Dictator Bush.
                  98.36% of all statistics are fiction.

Re: Reading Bad DVD Under 2.6.10 freezes the box.

[Xavier Bestel]

Le lundi 07 février 2005 à 08:05 -0500, linux-os a écrit :

> > Main Question >> Why does Linux 'freeze up' when W2K gives a BadCRC error msg 
> > (never freezes)?
> 
> Of course it should not. However, there were many incomplete changes
> made in 2.6.nn and some may involve problems with locking, etc.

I don't remember a version of the kernel gracefully handling scratched
CD/DVD.

	Xav

Re: Re: Reading Bad DVD Under 2.6.10 freezes the box.

[Justin Piszcz]

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Yeah, I can try 2.4.29 later tonight; also, the DVD is not scratched, just 
formatted with Joilet/ISO instead of UDF (which is what should be used on 
DVDs).

However, dd if=/dev/hdh of=file.img
          Even with bs=1 for 1 byte at a time, there seems to be no way to
          get the data off, however...

          With the dd, last time I tried it, it just fails.
          When I use cp to try and copy the file, it freezes the machine.

This is all under 2.6.10 with a Toshiba 16X DVD-ROM (I can get model 
number later.)


On Mon, 7 Feb 2005, Xavier Bestel wrote:

> Le lundi 07 février 2005 à 08:05 -0500, linux-os a écrit :
>
>>> Main Question >> Why does Linux 'freeze up' when W2K gives a BadCRC error msg
>>> (never freezes)?
>>
>> Of course it should not. However, there were many incomplete changes
>> made in 2.6.nn and some may involve problems with locking, etc.
>
> I don't remember a version of the kernel gracefully handling scratched
> CD/DVD.
>
> 	Xav
>
>

Re: Re: Reading Bad DVD Under 2.6.10 freezes the box.

[Xavier Bestel]

Le lundi 07 février 2005 à 09:17 -0500, Justin Piszcz a écrit :
> Yeah, I can try 2.4.29 later tonight; also, the DVD is not scratched, just 
> formatted with Joilet/ISO instead of UDF (which is what should be used on 
> DVDs).
> 
> However, dd if=/dev/hdh of=file.img
>           Even with bs=1 for 1 byte at a time, there seems to be no way to
>           get the data off, however...
> 
>           With the dd, last time I tried it, it just fails.
>           When I use cp to try and copy the file, it freezes the machine.

Does it work with ide-scsi ?

	Xav

Re: Reading Bad DVD Under 2.6.10 freezes the box.

[linux-os]

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On Mon, 7 Feb 2005, Xavier Bestel wrote:

> Le lundi 07 fÿÿvrier 2005 ÿÿ 08:05 -0500, linux-os a ÿÿcrit :
>
>>> Main Question >> Why does Linux 'freeze up' when W2K gives a BadCRC error msg
>>> (never freezes)?
>>
>> Of course it should not. However, there were many incomplete changes
>> made in 2.6.nn and some may involve problems with locking, etc.
>
> I don't remember a version of the kernel gracefully handling scratched
> CD/DVD.
>
> 	Xav
>

Well `cdparanoia` will read, analyze/rip, and reject trashed CDs
without ever hanging the Linux-2.4.22 kernel, but will immediately
hang linux-2.6.10.

Basically, when you start getting the kernel error messages on
linux-2.4.22, you can ^C out and everything will quiet down.
With Linux-2.6.10, nothing entered from the keyboard will
do anything. Since the Caps-Lock key still functions, interrupts
are still active. However, it is likely the kernel-lock that
prevents signals (like ^C or ^/) from being executed.

Cheers,
Dick Johnson
Penguin : Linux version 2.6.10 on an i686 machine (5537.79 BogoMips).
  Notice : All mail here is now cached for review by Dictator Bush.
                  98.36% of all statistics are fiction.

Re: Reading Bad DVD Under 2.6.10 freezes the box.

[Jan Knutar]

On Monday 07 February 2005 16:46, linux-os wrote:

> Basically, when you start getting the kernel error messages on
> linux-2.4.22, you can ^C out and everything will quiet down.

Not in my experience.

> With Linux-2.6.10, nothing entered from the keyboard will
> do anything. Since the Caps-Lock key still functions, interrupts
> are still active. However, it is likely the kernel-lock that
> prevents signals (like ^C or ^/) from being executed.

Speculations aside, I have found only one sure way of breaking
the eternal kernel-hang if you make the mistake of inserting a bad
CD into your drive; Needlehole eject.

Sure, the kernel will spit loads of error messages at you, but atleast
it wont be hung anymore, you can save work and reboot.

For eternal hangs when burning CDs though, I've found the only
reliable way of unhanging the system is to unplug power to the 
CD burner and replug it. This seems to cause some amount of
disk corruption to the master device on the same IDE channel
though, so I guess if you have two harddrives, like me, it is a
hard choice between risking corruption on both, and risking
corruption on one.

HTH

Re: Reading Bad DVD Under 2.6.10 freezes the box.

[David Gómez]

Hi Justin ;),

On Feb 07 at 07:32:48, Justin Piszcz wrote:
> Main Question >> Why does Linux 'freeze up' when W2K gives a BadCRC error 
> msg (never freezes)?

I don't know, but i can reproduce it too. I complained several months ago
about the problem (in 2.6.7/2.6.8 time) but nobody seemed to care :-/.

I think i still got the bad DVD, to try to reproduce the probelm in
2.6.10.

> The DVD FS is Joilet+ISO (hence, why none of the files are bigger than 
> 2GB), is this normal? 

Mine was Rockridge. It seems the contents are not important. The problem
is reproducible with any broken/scratched DVD.

regards,

-- 
David Gómez                                      Jabber ID: davidge@jabber.org