* Mark Rutland <mark.rutl...@arm.com> wrote:
> It still seems wrong to make up data, though.
So what we have here is a hardware quirk: we asked for user-space samples, but
didn't get them and we cannot expose the kernel-internal address.
The question is, how do we handle the hardware quirk. Since we cannot fix the
hardware on existing systems there's really just two choices:
- Lose the sample (and signal it as a lost sample)
- Keep the sample but change the sensitive kernel-internal address to
something
that is not sensitive: 0 or -1 works, but we could perhaps also return a
well-known user-space address such as the vDSO syscall trampoline or such?
there's no other option really.
I'd lean towards Vince's take: losing samples is more surprising than getting
the
occasional sample with some sanitized data in it.
If we make the artificial data still a meaningful user-space address, related
to
kernel entries, then it might even be a bonus, as users would learn to
recognize
it as: 'oh, skid artifact, I know about that'.
Thanks,
Ingo
