RE: [PATCH] Fix NULL pointer dereference in sd_revalidate_disk

[Jack Wang]

Should this need pick up into stable too?

Jack
Re: [PATCH] Fix NULL pointer dereference in sd_revalidate_disk
> 
> On Wed, Feb 22, 2012 at 10:01:53AM +0900, Jun'ichi Nomura wrote:
> > Since 2.6.39 (1196f8b), when a driver returns -ENOMEDIUM for open(),
> > __blkdev_get() calls rescan_partitions() to remove
> > in-kernel partition structures and raise KOBJ_CHANGE uevent.
> >
> > However it ends up calling driver's revalidate_disk without open
> > and could cause oops.
> >
> > In the case of SCSI:
> >
> >   process A                  process B
> >   ----------------------------------------------
> >   sys_open
> >     __blkdev_get
> >       sd_open
> >         returns -ENOMEDIUM
> >                              scsi_remove_device
> >                                <scsi_device torn down>
> >       rescan_partitions
> >         sd_revalidate_disk
> >           <oops>
> >
> > Oopses are reported here:
> > http://marc.info/?l=linux-scsi&m=132388619710052
> >
> > This patch separates the partition invalidation from rescan_partitions()
> > and use it for -ENOMEDIUM case.
> >
> > Reported-by: Huajun Li <huajun.li.lee@xxxxxxxxx>
> > Signed-off-by: Jun'ichi Nomura <j-nomura@xxxxxxxxxxxxx>
> 
> Acked-by: Tejun Heo <tj@xxxxxxxxxx>
> 
> Thank you!
> 
> --
> tejun
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