Buggy commit tracked to: "Re: [PATCH 2/9] iov_iter: move rw_copy_check_uvector() into lib/iov_iter.c"

['Greg KH']

On Fri, Oct 23, 2020 at 02:39:24PM +0000, David Laight wrote:
> From: David Hildenbrand
> > Sent: 23 October 2020 15:33
> ...
> > I just checked against upstream code generated by clang 10 and it
> > properly discards the upper 32bit via a mov w23 w2.
> > 
> > So at least clang 10 indeed properly assumes we could have garbage and
> > masks it off.
> > 
> > Maybe the issue is somewhere else, unrelated to nr_pages ... or clang 11
> > behaves differently.
> 
> We'll need the disassembly from a failing kernel image.
> It isn't that big to hand annotate.

I've worked around the merge at the moment in the android tree, but it
is still quite reproducable, and will try to get a .o file to
disassemble on Monday or so...

thanks,

greg k-h