On Thu 2020-05-28 11:03:43, Michael Ellerman wrote:

Petr Mladek [off-list ref] writes:

quoted

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@suse.com>

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@vger.kernel.org #v45.7 lines, please?

Best Regards,
Petr