Re: Instrumentation and RCU

[Thomas Gleixner]

Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> writes:
> ----- On Mar 10, 2020, at 12:48 PM, Thomas Gleixner tglx@xxxxxxxxxxxxx wrote:
>> How do you "fix" that when you can't reach the tracepoint because you
>> trip over a breakpoint and then while trying to fixup that stuff you hit
>> another one?
>
> I may still be missing something, but if the fixup code (AFAIU the code performing
> the out-of-line single-stepping of the original instruction) belongs to a section
> hidden from instrumentation, it should not be an issue.

Sure, but what guarantees that on the way there is nothing which might
call into instrumentable code? Nothing, really.

That's why I want the explicit sections which can be analyzed by
tools. Humans (including me) are really bad at it was demonstrated
several times.

Thanks,

        tglx