Re: [PATCH 1/3] bpf: Don't check for current being NULL

[Alexei Starovoitov]

On Tue, Oct 17, 2017 at 12:23:13AM +0200, Richard Weinberger wrote:
> Alexei,
> 
> Am Dienstag, 17. Oktober 2017, 00:06:08 CEST schrieb Alexei Starovoitov:
> > On Mon, Oct 16, 2017 at 11:18 AM, Richard Weinberger <richard@xxxxxx> wrote:
> > > current is never NULL.
> > > 
> > > Signed-off-by: Richard Weinberger <richard@xxxxxx>
> > > ---
> > > 
> > >  kernel/bpf/helpers.c | 12 ------------
> > >  1 file changed, 12 deletions(-)
> > > 
> > > diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
> > > index 3d24e238221e..e8845adcd15e 100644
> > > --- a/kernel/bpf/helpers.c
> > > +++ b/kernel/bpf/helpers.c
> > > @@ -120,9 +120,6 @@ BPF_CALL_0(bpf_get_current_pid_tgid)
> > > 
> > >  {
> > >  
> > >         struct task_struct *task = current;
> > > 
> > > -       if (unlikely(!task))
> > > -               return -EINVAL;
> > > -
> > 
> > really? in all context? including irq and nmi?
> 
> I would be astonished current is NULL in such a context.
> 
> To be sure, let's CC linux-arch.
> IIRC I talked also with Al about this and he also assumed that current
> cannot be NULL.

Hmm I probably mistakenly stole the !current check from somewhere.
Happy to delete all these checks then.