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

David Laight David.Laight at ACULAB.COM
Mon Nov 2 20:06:38 AEDT 2020


From: 'Greg KH'
> Sent: 23 October 2020 15:47
> 
> 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...

Did this get properly resolved?

	David

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