Re: Linux 3.0 oopses when pulling a USB CDROM

Andi Kleen
2011-07-03T01:16:30Z

> > if (trace_scsi && dev->type == &scsi_dev_type &&
> > trace_scsi_dev[0] == 0 || !strcmp(dev_name(dev), trace_scsi_dev))) {
> > dev_printk ...
>
> These extra puts could be coming from deep inside the device-model
> core, where they operate directly on the underlying kobject instead of
> going through put_device(). For example, removal of sysfs symlinks
> could have this effect.

Ok I could move it to kobject with some complications (need a real
back trace then)

> On my system, at least, the scsi_device's refcount dropped to 0 at the
> right time. That wasn't the problem. The NULL pointer occurs because
> the request_queue is used after the scsi_device has been removed from
> visibility; among other things, __scsi_remove_device() sets
> sdev->request_queue->queuedata to NULL.
>
> As the comment says, this causes the request function to reject all I/O
> requests -- but not before trying to dereference the NULL pointer!

Your explanation completely contradicts what James wrote earlier.

Maybe it's good if you guys come up with a common avenue of debugging
before I try further.

-Andi

--
ak-VuQAYsv1563Yd54FQh9/CA@public.gmane.org -- Speaking for myself only.
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at http://vger.kernel.org/majordomo-info.html