Re: [PATCH] powerpc/bpf: Enable bpf_probe_read{, str}() on powerpc again

[Daniel Borkmann]

On 5/28/20 2:23 PM, Michael Ellerman wrote:
> Petr Mladek <pmladek@xxxxxxxx> writes:
> > On Thu 2020-05-28 11:03:43, Michael Ellerman wrote:
> > > Petr Mladek <pmladek@xxxxxxxx> writes:
> > > > The commit 0ebeea8ca8a4d1d453a ("bpf: Restrict bpf_probe_read{, str}() only
> > > > to archs where they work") caused that bpf_probe_read{, str}() functions
> > > > were not longer available on architectures where the same logical address
> > > > might have different content in kernel and user memory mapping. These
> > > > architectures should use probe_read_{user,kernel}_str helpers.
> > > >
> > > > For backward compatibility, the problematic functions are still available
> > > > on architectures where the user and kernel address spaces are not
> > > > overlapping. This is defined CONFIG_ARCH_HAS_NON_OVERLAPPING_ADDRESS_SPACE.
> > > >
> > > > At the moment, these backward compatible functions are enabled only
> > > > on x86_64, arm, and arm64. Let's do it also on powerpc that has
> > > > the non overlapping address space as well.
> > > >
> > > > Signed-off-by: Petr Mladek <pmladek@xxxxxxxx>
> > >
> > > This seems like it should have a Fixes: tag and go into v5.7?
> >
> > Good point:
> >
> > Fixes: commit 0ebeea8ca8a4d1d4 ("bpf: Restrict bpf_probe_read{, str}() only to archs where they work")
> >
> > And yes, it should ideally go into v5.7 either directly or via stable.
> >
> > Should I resend the patch with Fixes and
> > Cc: stable@xxxxxxxxxxxxxxx #v45.7 lines, please?
>
> If it goes into v5.7 then it doesn't need a Cc: stable, and I guess a
> Fixes: tag is nice to have but not so important as it already mentions
> the commit that caused the problem. So a resend probably isn't
> necessary.
>
> Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
>
> Daniel can you pick this up, or should I?

Yeah I'll take it into bpf tree for v5.7.

Thanks everyone,
Daniel