Re: Yet another hot unplug NULL pointer dereference (was Re: statusof oops in sd_revalidate_disk?)

[Bart Van Assche]

On Tue, Feb 14, 2012 at 12:34 PM, Jun'ichi Nomura
<j-nomura@xxxxxxxxxxxxx> wrote:
> While scsi_device is propery refcounted object,
> q->queuedata is set to NULL by scsi_remove_device() asynchronously.
> So every reader of scsi_device's q->queuedata should always check it.

As far as I can see this patch narrows the race window but doesn't fix
the race. At least sd_prep_fn() still reads queuedata and if I'm not
mistaken that read races with scsi_remove_device(). Has it been
considered to modify scsi_remove_device() and scsi_request_fn() such
that device removal is communicated from the former to the latter in
another way than by clearing queuedata ?

Bart.
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