Re: [PATCH] kref: Avoid null pointer dereference after WARN

[Jason A. Donenfeld]

On Tue, Jun 27, 2017 at 09:06:26AM +0200, Greg Kroah-Hartman wrote:
> I remember one complaint was that WARN_ON was "huge" and this bloated
> the kernel code a lot.  But then that got fixed up.  Is BUG_ON going to
> cause the same complaint again?

Complaint or not, I'm pretty sure using BUG_ON here is the right
behavior. If removing it will result in a null pointer dereference (and
subsequent function call), that's bad news bears, especially on systems
with a zero mmap_min_addr or combined with other bugs.

If somehow a driver manages to pass a NULL as the release function,
something is really messed up and the kernel should "safely" panic
instead.

> 
> thanks,
> 
> greg k-h

-- 
Jason A. Donenfeld
Deep Space Explorer
fr: +33 6 51 90 82 66
us: +1 513 476 1200
www.jasondonenfeld.com
www.zx2c4.com
zx2c4.com/keys/AB9942E6D4A4CFC3412620A749FC7012A5DE03AE.asc