[RFC] BPF fault/jitter-injection framework

[Sergey Senozhatsky]

Greetings,

I've been thinking what if we had a BPF jitter/fault injection framework
for more fine-grained and configurable kernel testing.  Current fault
injection doesn't support function arguments analysis, with BPF we
can have something like

    // of course bpf_schedule_timeout() doesn't exist yet
    call bpf_schedule_timeout(120) in blk_execute_rq(rq) if
    rq->q->disk->major == 8 && rq->q->disk->first_minor == 0

So that would introduce blk request execution timeouts/jitters for a
particular gendisk only.  And so on.

Has this been discussed before?  Does this approach even make sense
or is there a better (another) way to do this?