Re: KASAN: slab-out-of-bounds Read in bacpy

From: Linus Torvalds
Date: Sun Mar 17 2019 - 12:35:27 EST

On Sun, Mar 17, 2019 at 3:43 AM syzbot
<syzbot+660883c56e2fa65d4497@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
> syzbot has bisected this bug to:
> commit c470abd4fde40ea6a0846a2beab642a578c0b8cd
> Author: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
> Date: Sun Feb 19 22:34:00 2017 +0000

Heh. Yeah, I doubt it.

It would probably be good if syzbot did some confidence testing before

Don't get me wrong, "git bisect" is absolutely wonderful and has done
a ton to help us fix bugs, but bisection has one major downside: if
the bug you are bisecting isn't 100% repeatable, the bisection will go
off into the random weeds and give completely nonsensical results.
They won't even be *close*. What makes bisection so powerful is also
what makes it then completely random if there's even *one* mistaken
bisection point.

So it would probably be good to test each bisection point at least
twice, and if they don't agree, report it as being unbisectable rather
than give a random "this is what introduced the problem".