syzbot out of space?

[Taylor R Campbell]

https://syzkaller.appspot.com/bug?extid=5122979265438b78248e

Does someone need to free up some space before syzbot can continue?

[Aleksandr Nogikh]

These errors come from the fuzzed VM, not from syzbot itself.
It also found a reproducer:
https://syzkaller.appspot.com/text?tag=ReproSyz&x=14355d9d280000

Should we somehow additionally restrict ktrace?

[Taylor R Campbell]

> Date: Mon, 19 Jun 2023 19:28:55 +0200
> From: Aleksandr Nogikh <nog...@google.com>

>
> These errors come from the fuzzed VM, not from syzbot itself.
> It also found a reproducer:
> https://syzkaller.appspot.com/text?tag=ReproSyz&x=14355d9d280000
>
> Should we somehow additionally restrict ktrace?

Ah, well, yes... ktrace can write a lot to disk. If you ktrace the
process that forks all the syzkaller processes, that will be a lot of
traced system calls very rapidly!

There are still some bugs I haven't tracked down in ktrace itself that
syzbot found, so it may still be worthwhile to fuzz ktrace somehow,
but whatever this reproducer is doing (haven't looked closely) might
not be worth pursuing further.