Re: 2.6.26-rc9-git12: Reported regressions from 2.6.25

Alan Stern
2008-07-14T15:57:33Z

On Mon, 14 Jul 2008, Johannes Berg wrote:

> > > > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=11072
> > > > Subject : scsi-layer crash after usb storage device unplug
> > > > Submitter : Johannes Berg <johannes-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
> > > > Date : 2008-07-12 01:50 (2 days old)
> > > > Handled-By : Alan Stern <stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>
> > > > Patch : http://bugzilla.kernel.org/show_bug.cgi?id=11072#c3
> > >
> > > Alan, Greg?
> >
> > We haven't heard back yet from Johannes to confirm that the fix really
> > works. If it does, IMO the patch should go into 2.6.26.1.
> >
> > (In fact it might not be so easy to tell, since the failure is caused
> > be a race. Perhaps it would be best to submit the patch in any case.)
>
> I haven't had a chance to apply the patch, but given that to cause the
> oops to happen I had to unplug/replug the device at random intervals for
> probably 10 minutes (yes, it took me that long to figure out I had put
> an SDHC card into an SD reader) I suppose it really won't be easy to
> tell.

Add

printk(KERN_ALERT "Unplug now!\n");
ssleep(10);

to the start of slave_configure() in drivers/usb/storage/scsiglue.c.
Then it should be very easy to trigger the failure. :-)

Assuming the failure does occur without the patch, see if it still
occurs once the patch is in place.

Alan Stern