Messages in this thread | | | Date | Sun, 3 Jul 2011 03:16:30 +0200 | From | Andi Kleen <> | Subject | Re: Linux 3.0 oopses when pulling a USB CDROM |
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> > 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@linux.intel.com -- Speaking for myself only.
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