Re: mmotm 2019-08-27-20-39 uploaded (objtool: xen)

Josh Poimboeuf
2019-08-28T20:01:42Z

On Wed, Aug 28, 2019 at 10:56:25AM -0700, Randy Dunlap wrote:
> >> drivers/xen/gntdev.o: warning: objtool: gntdev_copy()+0x229: call to __ubsan_handle_out_of_bounds() with UACCESS enabled
> >
> > Easy one :-)
> >
> > diff --git a/tools/objtool/check.c b/tools/objtool/check.c
> > index 0c8e17f946cd..6a935ab93149 100644
> > --- a/tools/objtool/check.c
> > +++ b/tools/objtool/check.c
> > @@ -483,6 +483,7 @@ static const char *uaccess_safe_builtin[] = {
> > "ubsan_type_mismatch_common",
> > "__ubsan_handle_type_mismatch",
> > "__ubsan_handle_type_mismatch_v1",
> > + "__ubsan_handle_out_of_bounds",
> > /* misc */
> > "csum_partial_copy_generic",
> > "__memcpy_mcsafe",
> >
>
>
> then I get this one:
>
> lib/ubsan.o: warning: objtool: __ubsan_handle_out_of_bounds()+0x5d: call to ubsan_prologue() with UACCESS enabled

And of course I jinxed it by calling it easy.

Peter, how do you want to handle this?

Should we just disable UACCESS checking in lib/ubsan.c?

--
Josh