Bug#1107479: util-linux: blkid hangs forever after inserting a DVD-RAM

[Ben Hutchings <benh@debian.org>]

On Sun, 2025-06-29 at 12:26 +0200, Uwe Kleine-König wrote:
> Hello Roland,
> 
> On Sun, Jun 29, 2025 at 11:46:00AM +0200, Roland Sommer wrote:
> > [correcting CC recipients]
> 
> Huh, how did I manage that (rhetorical question)? Thanks
> 
> > > Ahh, now that makes sense. pktsetup calls `/sbin/modprobe pktcdvd`
> > > explicitly, the blacklist entry doesn't help for that. Without the
> > > kernel module renamed, does the 2nd DVD-RAM result in the blocking
> > > behaviour?
> > 
> > Yes.
> 
> OK, that makes sense. So udev does in this order:
> 
>  - auto-load the module (which is suppressed with the backlist entry)
>  - call blkid (which blocks if the module is loaded)
>  - call pktsetup (which loads the module even in presence of the
>    blacklist entry).
[...]

I tested with a CD-RW, and the behaviour was slightly different:

- Nothing automtically created a pktcdvd device, so blkid initially
worked with a CD-RW inserted and the pktcdvd modules loaded.
- After running pktsetup to create the block device /dev/pktcdvd/0,
blkid and any other program attempting to open that device hung.

My conslusion is that pktcdvd is eqaully broken for CD-RWs.

Ben.

-- 
Ben Hutchings - Debian developer, member of kernel, installer and LTS
teams

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