Re: System crash with perf_fuzzer (kernel: 5.0.0-rc3)

[Vince Weaver]

On Fri, 1 Feb 2019, Jiri Olsa wrote:

> > 
> > I've just started fuzzing with the patch applied.  Often it takes a few 
> > hours to trigger the bug.
> 
> cool, thanks

I let it run overnight and no crash.

> > Added question about this bug.  It appeared that the crash was triggered 
> > by the BTS driver over-writing kernel memory.  The data being written, was 
> > this user controllable?  Meaning, is this a security issue being fixed, or 
> > just a crashing issue?
> 
> yea, I have an example that can trigger it immediately

I mean: the crash is happening because data structures are getting 
over-written by the BTS driver.  Depending who and what is doing this, 
this could be a security issue (i.e. if it was raw BTS data that was 
partially userspace controlled values).  Though even if this were the case 
it would probably be hard to exploit.

Vince