On Fri, May 29, 2020 at 03:57:51PM +0200, Christoph Hellwig wrote:
> On Thu, May 28, 2020 at 07:20:05PM +0200, Peter Zijlstra wrote:
> > > 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.
>
> Does it? If this is from the code in linux-next, then the code does a
> user_access_begin/end in csum_and_copy_{from,to}_user, then uses
> unsafe_{get,put}_user inside those function itself. But then they call
> csum_partial_copy_generic with the __user casted away, but without any
> comment on why this is safe.
Bah, clearly I was looking at the wrong tree. You're right, Al cleaned
it all up.
Let me try and figure out why objtool is unhappy with it.
