Subject: Re: USB Media card - works at boot-up, removal works, re-insert
	doesn't
From: David Zeuthen <david@fubar.dk>
To: Luke Kenneth Casson Leighton <lkcl@lkcl.net>
Cc: HAL list <hal@freedesktop.org>, kde-devel@mail.kde.org,
       linux-kernel@vger.kernel.org
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Date: Thu, 23 Sep 2004 21:31:40 +0200
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Hi,

On Tue, 2004-09-21 at 22:48 +0100, Luke Kenneth Casson Leighton wrote:
> > To me, it seems like a severe kernel bug if a userspace process,
> > *especially* if it's unprivileged, can keep the kernel from emitting
> > hotplug remove events when a device is physically detached. It would be
> > interesting to create a minimal program to reproduce this.
> 
> that's quite straightforward: i guess that an appx 30 character perl program
> or a 3 line python program 'd do the job.
> 
> or just using opendir() in c, here y'go...
> 

I can indeed reproduce this.

> [of course, changing it to "umount -lf" _also_ solves the
>  problem by making konqueror break: result, after the first remove,
>  you have to manually close konqueror, insert the media, remove
>  the media card (again), reinsert it (again), re-run konqueror]
> 

Even using 'umount -lf' doesn't work for me; I'm using the Fedora
Rawhide 2.6.8-1.584 kernel which is pretty close to 2.6.9-rc2-bk5. So
there we have it: unprivileged user can delay hotplug events for as long
as he likes. Yikes!

Thanks,
David

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