Re: [PATCH] s390/mm: Fix in_atomic() handling in do_secure_storage_access()

Alexander Gordeev
2025-06-04T17:29:41Z

On Wed, Jun 04, 2025 at 06:48:55PM +0200, Claudio Imbrenda wrote:
> > > @@ -441,6 +441,8 @@ void do_secure_storage_access(struct pt_regs *regs)
> > > if (rc)
> > > BUG();
> > > } else {
> > > + if (faulthandler_disabled())
> > > + return handle_fault_error_nolock(regs, 0);
> > >
> >
> > This could trigger WARN_ON_ONCE() in handle_fault_error_nolock():
> >
> > if (WARN_ON_ONCE(!si_code))
> > si_code = SEGV_MAPERR;
> >
> > Would this warning be justified in this case (aka user_mode(regs) ==
> > true)?
>
> I think so, because if we are in usermode, we should never trigger
> faulthandler_disabled()

I think I do not get you. We are in a system call and also in_atomic(),
so faulthandler_disabled() is true and handle_fault_error_nolock(regs, 0)
is called (above).

>
> >
> > > mm = current->mm;
> > > mmap_read_lock(mm);
> > > vma = find_vma(mm, addr);