Re: mmotm 2020-05-13-20-30 uploaded (objtool warnings)

[Peter Zijlstra]

On Thu, May 14, 2020 at 08:32:22AM -0700, Randy Dunlap wrote:
> On 5/13/20 8:31 PM, Andrew Morton wrote:
> > The mm-of-the-moment snapshot 2020-05-13-20-30 has been uploaded to
> > 
> >    http://www.ozlabs.org/~akpm/mmotm/
> > 
> > mmotm-readme.txt says
> > 
> > README for mm-of-the-moment:
> > 
> > http://www.ozlabs.org/~akpm/mmotm/
> > 
> > This is a snapshot of my -mm patch queue.  Uploaded at random hopefully
> > more than once a week.
> > 
> > You will need quilt to apply these patches to the latest Linus release (5.x
> > or 5.x-rcY).  The series file is in broken-out.tar.gz and is duplicated in
> > http://ozlabs.org/~akpm/mmotm/series
> > 
> > The file broken-out.tar.gz contains two datestamp files: .DATE and
> > .DATE-yyyy-mm-dd-hh-mm-ss.  Both contain the string yyyy-mm-dd-hh-mm-ss,
> > followed by the base kernel version against which this patch series is to
> > be applied.
> 
> 
> on x86_64:
> 
> arch/x86/lib/csum-wrappers_64.o: warning: objtool: csum_and_copy_from_user()+0x2a4: call to memset() with UACCESS enabled
> arch/x86/lib/csum-wrappers_64.o: warning: objtool: csum_and_copy_to_user()+0x243: return with UACCESS enabled

Urgh, that's horrible code. That's got plain stac()/clac() calls on
instead of the regular uaccess APIs.

Anybody any clue about what the best way forward here is?

Also, I wonder how we get at memset() with AC set,..