Re: [PATCH] ARM: Convert BUG() to use unreachable()

Joe Buck
2009-12-17T19:14:19Z

On Thu, Dec 17, 2009 at 11:06:13AM -0800, Russell King - ARM Linux wrote:
> On Thu, Dec 17, 2009 at 10:35:17AM -0800, Joe Buck wrote:
> > Besides, didn't I see a whole bunch of kernel security patches related
> > to null pointer dereferences lately? If page 0 can be mapped, you
> > suddenly won't get your trap.
>
> Page 0 can not be mapped on ARM kernels since the late 1990s, and this
> protection is independent of the generic kernel.
>
> Milage may vary on other architectures, but that's not a concern here.

I don't understand, though, why you would want to implement a generally
useful facility (make the kernel trap so you can do a post-mortem
analysis) in a way that's only safe for the ARM port.