Re: linux-next: Tree for Oct 18 (objtool)

[Christian Brauner]

On Mon, Oct 21, 2019 at 03:47:59PM +0200, Peter Zijlstra wrote:
> On Mon, Oct 21, 2019 at 03:19:48PM +0200, Christian Brauner wrote:
> > On Mon, Oct 21, 2019 at 03:11:49PM +0200, Peter Zijlstra wrote:
> 
> > > By popular request; here's that alternative. Completely untested :-)
> > 
> > Am I not getting some mails? :)
> 
> You're not on the 'right' IRC channels :-)

Well, we saw that that wasn't true today. :)

> 
> > I prefer this one as it allows us to avoid working around this in
> > usercopy.c. Should especially make if this potentially helps in other
> > cases as well?
> 
> That was Josh's argument too.
> 
> Personally I think GCC is being a moron here, because with value range
> analysis it should be able to prove the shift-UB cannot happen (the <
> sizeof(unsigned long) conditions on both), but alas, it emits the UBSAN
> calls anyway.

Ok, so I take it you route that patch somehwere through tip?
I'm happy with the ubsan fix:

Acked-by: Christian Brauner <christian.brauner@xxxxxxxxxx>