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

From: Michael Ellerman
Date: Thu May 28 2020 - 08:23:42 EST

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

Acked-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>

Daniel can you pick this up, or should I?