Re: [PATCH v2 01/11] x86: kcov: disable instrumentation of arch/x86/kernel/tsc.c

[Alexander Potapenko]

> Anyway, looking at kcov again, all the __sanitize_*() hooks seem to have
> check_kcov_mode(), which in turn has something like:
>
>  if (!in_task() ..)
>    return false;
>
> Which should be filtering out all these things, no? If this filter
> 'broken' ?

I think this is one of the cases where we are transitioning to the IRQ
context (so the coverage isn't really interesting for the fuzzer), but
still haven't bumped preempt_count.

In this particular case in_task() is 1, in_softirq_really() is 0, and
preempt_count() is 2.