ubiblock: null pointer dereference using scatterlist in work_queue

[hch]

On Wed, Aug 09, 2023 at 04:10:59PM +0200, Stephan Wurm wrote:
> Am 09. Aug 15:53 hat hch geschrieben:
> > Well, a scatterlist culd contain a highmem page, in which case sg_virt
> > isn't going to cut it and you need to kmap.  Is this a 32-bit system
> > with highmem enabled?
> I can confirm it is a 32-bit system with highmem enabled.

Yes.  So the code needs to stop using sg_virt to work on highmem
setups and do the equivalent of scsi_kmap_atomic_sg.  Best way
forward is probably to move scsi_kmap_atomic_sg to lib/scatterlist.c
(and also convert it to kmap_local instead of kmap_atomic while you're
at it) and then use that in ubiblock