Re: OOPS in scsi generic stuff 2.4.10-pre6

[Douglas Gilbert]

Jens Axboe wrote:
> 
> On Sun, Sep 16 2001, Jens Axboe wrote:
> > It looks like a race in that sg_cmd_done_bh can be completed before
> > generic_unplug_device is called (and thus on a free'd scsi request). We
> > then pass an invalid queue to generic_unplug_device.
> 
> (corrected version, scsi_allocate_request can of course fail)

Jens,
Prior to this patch (actually the first one you posted
today) sg_dd would frequently crash in generic_unplug_device
when tested against the scsi_debug adapter driver. [I have 
hacked up that driver to simulate a large number of (ram) 
disks to test Richard Gooch's 2000+ scsi disk patch.]

The way scsi_debug handles all its commands, the bottom
half handler in sg will be called before scsi_do_req()
completes. With this patch the problem goes away.

Doug Gilbert