Re: [PATCH 18/20] objtool: Add UACCESS validation

[Peter Zijlstra]

On Thu, Mar 07, 2019 at 08:33:26AM -0800, Linus Torvalds wrote:
> On Thu, Mar 7, 2019 at 3:52 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> >
> > XXX: are we sure we want __memset marked AC-safe?
> 
> It's certainly one of the safer functions to call with AC set, but it
> sounds wrong anyway. It's not like it's likely to leak kernel data
> (most memset's are with 0, and even the non-zero ones I can't imagine
> are sensitive - more like poison values etc).
> 
> What's the call site that made you go "just add __memset() to the list"?

__asan_{,un}poinson_stack_memory()
  kasan_{,un}poison_shadow()
    __memset()