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Message-ID: <84144f020704020007x879f781x45f395298d92cbe@mail.gmail.com>
Date: Mon, 2 Apr 2007 10:07:31 +0300
From: "Pekka Enberg" <penberg@cs.helsinki.fi>
To: "Rene Herman" <rene.herman@gmail.com>
Subject: Re: mcdx -- do_request(): non-read command to cd!!
Cc: "Jens Axboe" <jens.axboe@oracle.com>, "Al Viro" <viro@ftp.linux.org.uk>,
       "Linux Kernel" <linux-kernel@vger.kernel.org>
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Hi Rene,

On 4/2/07, Rene Herman <rene.herman@gmail.com> wrote:
> root@5va2:~# dd if=/dev/mcdx0 of=/dev/null bs=2048
> 0+0 records in
> 0+0 records out
> 0 bytes (0 B) copied, 0.000221955 seconds, 0.0 kB/s
> root@5va2:~#
>
> This I know isn't:
>
> root@5va2:~# readcd dev=/dev/mcdx0 f=/dev/null
> Segmentation fault
> root@5va2:~#
>
> (leaves a "note: readcd[1174] exited with preempt_count 1" in the log)
>
> and after a "mount -t iso9660 /dev/mcdx0 /mnt/cdrom",  a:
>
> root@5va2:~# tar cv /mnt/cdrom >/dev/null
>
> has upto now done all of:

[snip]

Try with CONFIG_PREEMPT_NONE as suggested by Jens. Can we see strace
for the dd, readcd, and tar runs, please?